I naively still had hope going into seeing ROTS, even after TPM and AOTC, but ROTS gutted me as a fan. Interesting the contrast for you with TROS after TFA, and maybe with TLJ too? Or it being directed by JJ again, or something else?
For a while after seeing TFA, I was unsure whether it was actually a bad movie or if it was just me. I wondered whether I might just not be able to enjoy Star Wars anymore. Rogue One proved that wrong, though.
Going into TLJ, I was very doubtful but still had a sliver of hope, and while TLJ was marginally better than TFA, it wasn’t better enough to make me care about the trilogy story. And it firmly cemented to me that the ST didn’t know where it was going and was damaging to the original films. (That’s a big part of why I got into the EU. I wanted some sort of alternative outcome for the OT characters. I didn’t want the ST to be the only possible future for those characters.)
Besides that, my main reason for having no hopes for TRoS was that I’d read the plot leaks and heard early word-of-mouth about the movie, so I knew what I was in for.