Thanks very much for this. I've been hoping that raltsm4k updates Floating Subs List to incorporate collections, but they haven't been active since mid-last year.
Given your code is partly based on this script, I wonder if you might consider modifyingraltsm4k's Floating Subs List script so that collections appear as part of the sidebar. As a fallback, maybe modify your script so that collections appear before magazines rather than after. This would make it easier to use both scripts, one to access magazines in the sidebar, and the other to more easily access liked collections.