I've been trying various Linux flavours every year for 10 years or so. The last year I tried Arch, then EndeavourOS, which has been my most successful Linux exploration I've ever had, and given me huge hope. However, there are still a few things preventing me switching it to my default OS.
I'll put aside Games that need Anti Cheat, as I doubt that will ever be fully fixed, unless Governments force game devs to support more than just Windows.
Here is what doesn't work for me:
- Streaming services like NowTV. (Works in Windows in browser only)
- DRM proected VST's for use with Reaper (not via Wine)
- Roblox (Using Waydroid was not very successful)
- Office 365 (I like Libreoffice and OnlyOffice but fact is Word and Excel are just required for some stuff)
1 and 2, there's also the option to still buy it but then download a pirated copy that actually works. In a professional setting at least, if you sell stuff made with the pirated software you have the license and rights to do so. Personally I would rather skip the plugin entirely, but if you must, and you must legally-ish, that's an option.