To be fair, Michael and Jane were together for two years, and she dumped him for his bad behavior and immediately got together with that guy she kissed once five years ago. And after that they were on and off, got married, then Michael was in hospital, then they had a couple months all to themselves (while they were fighting and Jane obviously was hang up on Rafael dating other women, while repressing that like crazy), and then Michael died.
I think fans were always way over-invested in Jane/Michael when the show itself never was, that's why where all of those
1) "Rafael is just hot muscular guy, also he's boring" (this is super subjective, and building any theories of one pairing being better than the other on that alone will lead nowhere)
2) "Jane and Rafael are not built enough/badly". (That's called confirmation bias, and by default is subjective). Jafael has the strongest support in-the show and in the BHS interviews alike. It was called the definite endgame in season 3 scripts.
3) "But Jane and Rafael always fight!" (compared to Michael being Jane's doormat and lying to her about his feelings) opinions I keep on seeing.
All of that reminds me a lot of any fandom ship war, when fans are trying to spin a narrative by blatantly erasing events and connections between couple they don't like. It works better in movies/tv shows where there's a up-in-the-air love triangle, though (like Damon vs Stefan, Pacey vs Dawson, Jack vs Sawyer). When any engdame is obvious from the start (like Ron/Hermione, Jane/Rafael, Jane/Rochester, Elizabeth/Darcy, etc), then it gets complicated for opposing shippers.
I also don't think I want to recap all five seasons of the show to prove the endgame ship's legitimacy that was obvious from the first episode. I'd rather watch it for my enjoyment. Mostly because I don't have to prove anything, Jane (female lead) and Rafael (male lead) are married and endgame.