2022 Annual Report on Unidentified Aerial Phenomena

1 Hovering while overcoming the earth’s gravity with no visible means of propulsion.
2 Sudden and instanteneous acceleration.
3 Hypersonic velocities without signatures.

This 'signature' could point to a breakthrough technology as yet unavailable to us.
I think it's even more likely that it points to a mistaken identity, in which the size, distance, and/or speed are unknown, just calculated based on what it looked like to the person reporting it. If it doesn't interact with the atmosphere in the way that would be expected, something is wrong with the story. If you don't really know the size, you don't know the distance or speed, period. If it's something illuminated (such as a view of jet engines), any photo will look bigger than it actually is. And if it's not really an object at all (such as a reflection or mirage) then you can throw ALL the observer's assumptions of size or acceleration out the window.

We've all seen pictures of mysterious and enormous "things" that turn out to be an insect on the lens.
In the earliest UFO days - the late 40's - UFO's were often described as quite small. For example, baseball sized.
What we do know beyond reasonable doubt:

-We'll keep getting UFO reports
-People will think this is the dawn of a new era in human history
-Nothing will happen
A "cigar shape" (cigars were more popular than tic-tacs in those days) was reported in 8,3% of the cases.
A "triangular" shape was reported in 2% of the cases.
A "disc" was reported in 26% of the cases.

So tic-tacs ('cigars') were quite common in the early years and triangles were also occasionaly observed.
Except, cigars weren't all that common, especially as compared to saucers. As your NICAP report shows, from '42-'63 58% were geometrical while only 8.3% were Rocket or Cigar-shaped. Then it mentions a separate Air Force report of a much larger sample, 2199, from '47-'52 in which an even smaller 5.2% were rocket like. I think Cigar/rockets became more popular as the Gemini/Appolo programs got going.

I'm not sure Cigar and Tic Tak are necessarily the same thing:

why would ET drive the same model for 70 years? ;)

Yes, who doesn't want the new model? My truck is pushing 8 years old now, but hey, it's paid for. Maybe it's the same with the aliens, they invested all that money in a FTL starship and they want to get their money's worth. :D

Despite the variation in shapes, three of the 'five observables' have been present since the first UFO sightings:
1 Hovering while overcoming the earth’s gravity with no visible means of propulsion.
2 Sudden and instanteneous acceleration.
3 Hypersonic velocities without signatures.

I don't know, the so-called "5 observable's" was coined by Louis Elizondo, former self-confessed head of the DoD AATIP program. Except there was no such thing, not officially:

"Five Observables" is a term used by UFO researcher Luis Elizondo to describe the extraordinary traits shared by some UFOs:

  • Anti-gravity: UFOs seem to be able to generate lift, without any visible propellers, wings, or rocket propellant. This may be a form of antigravity that is yet to be discovered by humans.
  • Instant acceleration: Many UFOs are observed accelerating extremely quickly, beyond any known object. This acceleration creates massive g-forces that would normally crush any ship or its occupants.
  • Hypersonic speed without signatures: UFOs have been seen traveling at several times the speed of sound. Normally, hypersonic speeds should create loud sonic booms, but UFOs seem to travel silently.
  • Low observability: UFOs seem to have the ability to avoid detection, cloaking themselves from radar and visual instruments. When they are detected, they sometimes disappear without warning.
  • Trans-medium travel: Some UFOs seem to travel effortlessly between space, air, and water. That means they can withstand a huge range of pressure, from the high pressure of the ocean to the low (almost nonexistent) pressure of space - and they can maneuver through all three mediums.
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I would think of something like, "at mid-day with no clouds the sky appears blue" or "on a clear day the sun is seen rising in the East" as "Observables".

Elizondo's 5 observables just seem more like categories for what people saw, or thought they saw or claimed to have seen. And as @Ann K pointed out above, all of these observables could just as easily be mundane things.

This 'signature' could point to a breakthrough technology as yet unavailable to us.

Or it could be a bug zipping across the screen. Or it could be parallax. Or it could be a targeting system losing tracking. Or any number of non "breakthrough technologies".
Remember, many of the UFO/UAP "shapes" have changed over the years. From the late '40s it was the "flying saucer" based on the Kenneth Arnold sighting (bold by me):

This was the first post-World War II sighting in the United States that garnered nationwide news coverage and is credited with being the first of the modern era of UFO sightings, including numerous reported sightings over the next two to three weeks.

Arnold's description of the objects also led to the press quickly coining the terms flying saucer and flying disc as popular descriptive terms for UFOs
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This continued through the "80s with popular hoaxes like the Gulf Breez photos using the flying saucer:

Starting in the '80s and into '90s the "black triangle" became popular (bold by me):

During the early 1980s several hundred people claimed to have witnessed UFOs flying over, or near to, the Hudson River in New York state. These sightings involved hovering or slowly-flying, V-shaped objects rimmed with colorful lights.
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The Belgian UFO wave began in November 1989. The events of 29 November were documented by over thirty different groups of witnesses, and three separate groups of police officers. All of the reports related a large object flying at low altitude. The craft was of a flat, triangular shape, with lights underneath.
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A widely reported appearance(s) of black triangles involved the "Phoenix Lights" events, during which multiple unidentified objects were observed near Phoenix, Arizona and videotaped by both the local media and residents beginning on Thursday, March 13, 1997.
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These days, it's the Tic Tak, which is just a way of saying an indistinct blob that is wider than it is tall. That's only since the release of the Navy videos in 2015, though I'm not sure when the phrase was actually coined:

Underwood recorded the FLIR video, and coined the description "Tic Tac" to describe the infrared image, but did not himself see any unusual object.[9]
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After each initial sightings, lots more followed seeing the same shape as each new shape became popular.

I'm just suggesting that the "shapes" of UFO/UAP are as much a part of the popular zietgeist as much as any actual observations.
That still does not explain why common UAP shapes would be classified and redacted. Cigar shape UFOs and lozenge shape ufos have been observed in the 1950s,60s,70s... Present day with the new name tic tac, it's still the same shape from decades ago.

So why is the DoD classifying common shapes?
Maybe in case an adversary has a particular shaped drone they are using to spy on us.
Or to ensure that any new sightings aren't affected by old ones. For example, if an F-18 pilot said he saw a UFO that was, say, shaped like a minty breath freshener - it might result in hundreds of false UFO sightings of similarly shaped craft.