I beg to differ. Endgame really only had to wrap up Tony, Cap, Black Widow, and Thanos. The other major players had pretty standard arcs - Thor, Hulk, Hawkeye, Ant-Man, and Nebula - while everyone else was basically missing for 95% of the runtime.
TROS has to completely wrap up Leia, Rey, Kylo, Finn, Poe, Chewey, and C-3PO/R2-D2, introduce two new characters (Zorii Bliss and Jannah), re-introduce and wrap-up Lando and Palpatine, while also servicing not only to Luke in some way, but also wrap up nearly 60 years worth of story (in-movie, 40+ years in our world), not to mention possible cameo appearances by Yoda, Obi-Wan, Anakin, etc. I would argue that this movie has far more heavy lifting to do in terms of wrapping up characters and answering questions than Endgame, which had the benefit of having an entire other movie immediately prior in Infinity War to further lay the ground work for the end of all of those arcs, and then had the luxury of keeping most of its other characters going past that point. TROS not only has to follow TLJ, which basically did the opposite of Infinity War and essentially reset the narrative, it has to end EVERYTHING.
That, and if the leaked story beats are to be believed, I don't see how this movie fits into the standard 2h 15m runtime anyway. Three hours might be pushing it, but 2h 45m wouldn't surprise me at all.