> One side invaded the capital building in a violent attempt to overthrow democracy
Okay so lumping together half the country in with a few extremists would probably be the first step to answering your question. Yes there were probably plenty of people at home cheering them on but if you really believe it was half the country then you need to get outside your bubble.
> the other side wants to make voting for whoever you want as easy as possible
I have a tough time believing this at least from a party perspective. Sure, the democratic party loves to say this, and they even manage to back it up with their actions sometimes when it's convenient for them, but they still only want you voting for their party approved puppets. If that weren't the case then I simply don't see how it is defensible for democrats to not have enacted a better voting system yet in places where they have clear majorities (eg California would be near the top of that list, and yet here we are stuck with a democratic governor who vetoed the legislation which would have allowed general law cities to use alternative voting systems). Note that I find it entirely likely that plenty of democratic voters would like to fix our voting, I'm specifically talking about the party leadership here, although on that note there are also plenty of republicans who would like to fix our voting, so that's another step you could take to meet them in the middle.
First past the post voting is probably the biggest thing preventing people from "voting for whoever they want", but democrats have done very little for that even though it is blindingly obvious how terrible of a system it is. Well, I can see why the democrats (and republicans) would like it, because that's a large part of how they stay in power, but from a "voting for whoever you want" perspective it's just about as bad as it gets and the democrats just don't seem to care about it.
Now that it's becoming clear that more voters care about this reform, many places are turning to RCV/IRV as the solution when there are much better methods out there. It's hard to tell if it's just being ignorant about the problems with IRV (eg doesn't elect condorcet winner, ignores lots of ballot preferences, non-monotonic, etc) or if they are intentionally aiming for a method which appeases the voters while also being one that will help keep them in power. Approval and STAR are significantly better and are gaining momentum in the US and any condorcet method would also be reasonable, but so far support for these other options is pretty grassroots and I'm unaware of any big name republians or democrats actually talking about those other methods.
Fixing the voting would also help people like you distinguish just how much support eg Trump has compared to others. There was a lot of vote splitting happening in the Republican primaries which Trump benefited from and with a proper method I believe it's entirely possible he wouldn't have even been nominated in the first place. There are plenty of Republicans who did not like him but didn't feel they had an alternative in the general election because of how distasteful they found Clinton/Biden to be.