Thanks guys for the suggestions and ideas.

I was debating between Windows 10 LTSC 2021 IoT (lightweight Windows version supported until 2032) and Windows 11 LTSC (supported 2035+ I think... but has "Recall" and more telemetry and bloatware etc. Seems like another Windows Vista or Windows 8 - not my cup of tea).

I think I'll go with Windows 10 LTSC 2021 IoT - less bloat, more stable... won't unlock the best hardware features for "modern" computer builds - but I hear in various aspects Win 10 LTSC is actually faster than 11.