I don’t have aac or vorbis files but FWIW can’t see a problem with mp3, neither within one album nor in an all-mp3 queue from different albums, as far as I can tell without finding continuous albums. At least no skips and jumps certainly. (I checked with Roon on Mac remote and ROCK to a RAAT endpoint, not ARC)
My understanding is that gapless should work if the protocol supports it like RAAT
There is one on the Roon help page for Chromecast though it doesn’t mention lossy files (but doesn’t exclude them either):
All Chromecast devices support gapless playback with Roon
My naive conclusion would be that it’s not worth mentioning for RAAT because it’s a given
As @Suedkiez says, gapless playback is a given with Roon, so if you’re getting “hicks and jumps” there’s an issue with your setup.
If you want the Support team to take a look, then please post in the #support category of the forum and fill out the post template with the full details of your setup to aid in diagnosis. I should warn you that the Support team is small, and has a backlog of issues that they are dealing with, so it could be a while before they can respond directly.