Surprisingly, I installed Calibre on Linux and for some reason it just looks...better on Linux? Not sure if its because it opened up in default dark mode or what, but it doesn't look as ugly when I'm using it on Pop_OS. Feels at home, really.
I will say its definitely a beast. I've used it a few times but I never really went in depth with it's features. I'm definitely liking the bulk tag editing, the shop search (I've been looking for a way to search DRM-free books and it has it!), and the default tags. The last one is mainly because I think getting a tag called "mentally ill women" for The Yellow Wallpaper is a little funny.
KDE Connect means that I can ping my phone that's usually presumably somewhere behind my bed or on a counter somewhere, without having to sheepishly walk to the nearest person and ask "can you call my phone I lost it :c"