To be fair it did feel like it was cramming too much in. One other complaint I had is that it covered about 30 years of history and yet neither Joaquin Phoenix nor Vanessa Kirby appeared to age a day. It would have benefited from just focusing on one part of his life/career IMO.
But ultimately yes, the impression I got from this and Gucci (less so the Last Duel, which was also overlong but worked a lot better due to the three-part format) is of a director who's just running out of fumes. It tracks, he's 85 years old! But he's clearly not a good enough judge of his own material to trim the fat, but also too powerful for anybody else to step in and demand changes. The man is in desperate need of a judicious editor.
I liked Killers of the Flower Moon a lot more, but I get a similar feeling from Scorcese and his recent spate of four hour epics.