As a Republican you are in an excellent position to help MB lefties or others like yours truly to understand how to even broach any of these themes constructively with 'conservatives'.
lol ive been trying to do that for 2 years now. I'm banging my head against a wall. There's a good book though on the subject, its called "Escaping the Rabbit Hole".
The very suggestion 'Biden was elected fairly'
that's subjective. it depends on how people are hearing "fairly". i think Biden won (like Bush won over the dimple controversy), but i wouldn't say Biden was elected "fairly". Covid was a very very unique and abnormal election year. All sorts of election rules were thrown out the window.
I would say "conservative judges, including the U.S. Supreme Court, haven't been presented with any evidence that Biden did not win the election. The sneaky tactics some states used during Covid were deemed 'irrelevant at this time' by conservative judges. Elections are far from perfect, but it is what it is. Biden is President"
(of course i would go on to explain to them why Biden winning is an excellent thing for our party long term.. and they will be happier, but they will still claim ..forever.. Biden did not win fairly. It's an opinion.)
I can't really speak for southern conservatives, or mid west unfortunately. They would probably view me as borderline left. But if i am now generally suspicious of anything i read on MB, i would imagine the more right folks aren't even going to bother to look up the claims made here.
Logic is lovely. But most people (on all sides of the aisle) do not make decisions based on logic.. if they did 75% of Dems would convert to conservatism!

People make decisions based on trust. For example, before the new summer delta surge, most of those who didnt want to get vaccinated were citing their friends and families as convincing them to get the vaccine.. not random propaganda from the media. (although case surges in their area still trumps all motivations ie. real life fear).
They trusted people who cared about them and loved them.
Personally i wouldnt waste my time on one-on-one politic debunking unless that person lives in a swing state. but if you do engage (from either side of the aisle) i would suggest reading "Escaping the Rabbit Hole". There are threads on MB that cover the same discussions and conclusions but I'm not sure how easy they are to find.