Detailed feedback?
Sorting mods can be done either by endorsements, downloads or "recently added". Sorting by file name, UDL, last comment or author name are gone (yes, sometimes author and uploader are not the same).
3 cards in a row vs 5 on old UI. IMO is a huge step back in usability and user experience.
Author and uploader fields are gone too.
Mod info layout is too cluttered and not logical enough (this point is subjective, card is cluttered anyway).
Profile info section eats huge 1/4 of useable space with absolutely no benefit. At least GitHub or Facebook have full-width content, that in case of Github at least scales to screen size properly.
Endless scrolling means harder finding mods on profiles with say 50+ files. Also makes it harder to pause watching through mods to return later (no, not 5min later, more like tomorrow).
Suggestions? Have some:
Return to page-based mod presentation.
Bring back extra sorting options.
Use huge extra empty padding on top to display account data (it's there so might as well use it).
Return to at least 4 or better 5 mods per row setup.
Display both author and uploader names.
Add at least one extra empty line between upload times, description and stats.
Expand available description to 5 or 6 rows.
Center mod list on screen.
One extra suggestion would be to force website scaling on large screens (I get it, mobile is a priority and currently it's not the best experience sometiems), but when content takes up at best 3/5 of screen space, with actual mod list measuring at 1/2 (and still not centered too), it's actually less convenient than what is now "old UI".