Welcome to the resistance! 😄
I did pretty much similar as you, but about a decade ago. Was it really Windows 8 at the time? 7 perhaps? Even then the OS was becoming increasingly bloated, and crudely implementing channels for Microsoft to milk data from users.
For me it wasn't so much editors and development environment that kept me around, but the Adobe suite — specifically the lack of CMYK support in FLOSS alternatives. In the end I was quite happy to just find workarounds for the few print jobs I would have to do.
Quite often I think people are less resisting a new OS environment than the software available. "I couldn't use the same shortcuts in [FLOSS package] as in [proprietary software], so I went back to Windows"...
I'm not exactly a hardcore Excel user myself, but I'd be interested to hear how your transition to LibreOffice (I guess the most viable alternative?) will work out.
Yeah, that was my thinking — that for most purposes LibreOffice will replace Microsoft Office fairly well. But I'm always keen to hear what bumps people run into when they switch from the latter. For you it seems there haven't been any worth mentioning?
Glad to hear it's gone so smoothly!