The only problems I have are regarding PDF files:
1) Dark mode (via dark reader) won't work on PDFs.
2) The Print-to-file (Ctrl + P) save location defaults to "~/mozilla.pdf" and there seems to be no option in preferences to change this default (titles often are multi-word long and copy pasting is a huge pain. Chrome just picks up the title of the webpage and the default downloads directory as the location, which IMO is the sensible thing to do.)
In my experience, Chrome is really better at handling PDFs (even better than the native reader, Okular, in terms of fine-grained zooming, dark theming(again via the Dark Reader extension.)) and I'm mulling over switching back, because I use pdfs a lot. (As for other stuff though, like lagginess, I don't find any noticeable difference.)