Again, it's not just about winning. Any primary candidate that gets a share of votes shifts the platform, it's the campaign that matters, like Bernie Sanders who wasn't even part of the DNC yet shifted the party/presidential platform after the primary.
Sure, there are some minimum requirements for running, it doesn't fundamentally change any dynamics here, it just raises the bar. It's always convenient for primary losers to blame their loss on party favor like Hillary's case, even though it simply amounts to increased marketing and exposure which, as was evident in the 2016 elections, does not win elections. As with all marketing, it only works by increasing the reach of an already good product, it does not mind control voters. I'm going to assume you personally did not vote for Hillary in any primary, you had no trouble resisting this diabolical collusion yet I suppose the implication here is that everyone else is just too weak minded to self-determine their own votes in the face of increased campaign financing. The simple reason you need to be a millionaire is that any serious party always has one or more massively popular candidates that already represent the majority of issues that voters care about, there are rarely any major gaps in representation, the easiest way most candidates can distinguish themselves when the main issues are already represented is by increasing exposure. But if voters care about a major gap in representation, they will find you. If you completely solve this problem by lowering minimum requirements to zero, it will simply change the minimum size of these relatively small gaps which also lets increasingly small & fringe extremists into the party.
> The problem we have now is that we're forced to vote for who is most likely to win no matter how we feel about them. There is research showing it would increase voter turnout and it would also open the door for more than just two parties expanding our options.
You are not forced to vote for who is most likely to win, every candidate knows that if they don't represent certain issues it will depress turnout and lose them votes. That's because people are not forced to vote for who is most likely to win, in fact they don't have to vote at all. In the next sentence you even point out that it will just increase voter turnout. Again, I don't doubt that, but the votes it accounts for are insignificant compared to voluntary abstinence, it's a minor distraction. Like I said before, it will at best equilibrium on the most borderline issues but parties will quickly realign. The same is true for gerrymandering, it has a suppressive effect but it does not defend against a serious consensus among actual voters, it simply raises the bar for one by a certain amount. You simply don't have a serious consensus on issues like marijuana and healthcare. A serious consensus is formed by voters prioritizing it in the voting booth, not answering "yes I care" on any of these academic studies.
For someone who seems so concerned that the system is largely broken you're awfully focused on only fixing the tiniest of cracks in the face of voluntary abstinence. This is the equivalent of fussing over expensive & fancy gym equipment to fix your workout when your biggest problem is that you don't workout often. Americans have never needed the most theoretically optimal voting systems or the best anti-gerrymandering policies at the cutting edge of democracy. They have democracy at home, if they have any problems they just have to use it.