A cracked version of W10LTSB with most of the cruft stripped out and updates/AV disabled is genuinely the best base computing experience. My WWAN card even works properly. Linux is happy inside a VM, and the host computer works properly without spending a billion hours recompiling drivers with every kind of weird lab hardware, GPUs, FPGAs, and it's own internals etc. If something is better supported on Linux I just pipe it into the VM.

Why not update it though? They promise 0 feature changes. Only security updates and bugfixes.

Although one possible problem could be if your hardware breaks down in five years and you want to take that as an opportunity to upgrade instead of doing a simple like-for-like replacement – drivers for then current hardware might not necessarily support old LTSB versions.

Well I think windows 11 has same kernal as 10? So probably drivers will be fine for a good few years also.

I think that's mainly backwards compatibility from the OS with regards to existing drivers, but Windows might still introduce some new APIs that hardware vendors might make use of, thereby rendering new drivers incompatible with older OSs.

Likewise, new CPU and/or chipset generations might require not just new drivers, but dedicated OS support, which in all likelihood won't be backported to the LTSB versions, either.