Like I do get much of the criticism because 3’s writing overall was weaker outside the Citadel DLC. The endings they picked didn’t really explore a lot of the ideas that were being built up (particularly the dark energy stuff that I still find really interesting and it does cheap out with the relationships between organic and technological life), and the original versions left things arguably a little too vague in the control ending, but every choice is thematically relevant for both Shepard (you get a paragon and renegade option in unexpected ways and a third option based on self-sacrifice, not to mention a really interesting forth option after patch) and the ongoing major story threads of the trilogy. Even if one ending looks goofy, I felt it all worked overall.
THAT SAID, I do think how the Geth stuff within the meat of the game itself was handled really badly because they outright threw out a major plot point established in 2 that could have taken the conflict in a much more interesting and complex direction. The game as a whole tries way too hard to simplify a lot of conflicts in general cause we all gotta go beat up the big evil colonialism metaphor so we don’t have time to do the colonialism we wanna do, which is honestly a pretty weak way to take the last chapter of the Shepard story line, but they did end it in a way that left me satisfied. It had proper closure.