starwars.com wrote an article officially explaining how Palpatine returned, somehow.

[Ushojax]

It was the best Star Wars movie since the originals and Rogue One. The ending gave me so much hope for 9. Then JJ came back and el-oh-el.

Click to shrink...

Same, TLJ has lots of flaws but I walked out of the cinema excited for where the story was going. When the credits rolled on TROS I just wished I could erase the memory of watching it.