There are ways to make constitution changes become more common without changing the 75% rule. I believe that the reason why changes have stopped is because of how deeply entrenched the two political parties have become. They know that they'll continue being in power if they don't make any changes. So, they just maintain the status quo with minimal changes.
Ranked choice voting is a way to force them to make the changes that people want or get voted out. Rn they can't be voted out as there are only two realistic options.
I agree with you that people should be able to decide what happens to their body without fear of retaliation. That's an amendment I would vote for.