I give you credit for at least engaging with a very difficult environment I think if you have some conservative leanings. I have some conservative leanings as well, and am coming from the perspective that in 2016, I would have considered voting for ANYONE over Hillary Clinton. (nothing to do with policy, she gives me a visceral and negative gut feeling that she is just not who I want to entrust the country to at all, and this is far beyond politics, only Ted Cruz has also made me react that way prior...and now Trump gives me that feeling) Trump also was a little more of an unknown in 2016, and there were red flags, but I think I can easily see that some voters would take a chance on Trump versus Clinton.
I'd say for myself the three worst things off the top of my head Trump has done (and thus he has lost my vote) are the following:
1) Diminished the dignity of the President as the leader of the country. For many people, this might not matter, but for me, I kind of would like the leader of our country to act in a way where children have an easy time admiring the person, even if they disagree 100% with their politics. I have no problem saying that priors like Obama or George Bush never ever in my mind damaged the actual office even though their politics are very different. People focus on the racial stoking and dog whistles, but I notice a lot more that so many things coming out of his mouth are outright lies. Most politicians lie and stretch the truth and such, but this is quite unique to me.
2) Trying to expand executive power (I have this same problem with Democrats too) in a way I don't like, as I favor a much more limited executive branch for certain functions in our government. I don't mind the idea that nothing happens - even at the expense of short-term gain - if a larger body of elected officials can't get something done versus a smaller concentration of power.
3) The COVID response - A lot of what transpired is just hard to defend -- you really can look at specific moments and what did and didn't happen and just scratch your head.
I'll be very transparent and say the issues I am tagged conservative here would be 1) guns 2) business/personal taxes and small business regulation and 3) national defense/military issues. I can admit I am much more a social liberal "country club" type on business/fiscal policies.
Definite not conservative leanings would be 1) abortion 2) trying to use religious freedom to discriminate and/or leech it into not separating church and state 3) favor a public health care option (but probably not in favor of a universal plan ONLY without other options) and 4) favor path to citizenship for immigrants given a set of clear rules to do so (no serious crimes and other benchmarks to show they would be a productive citizen)