Earlier quoted context omitted.
Fastest threadripper on the market is usually a good bet. Worth considering mini-pc on vesa mount / in a cable tray + fast machine in another room. Also, I've got a gmktec here (cheaper one playing thin client) and it's going to be scrapped in the near future because the monitor connections keep dropping. Framework make a 395 max one, that's tempting as a small single machine.
Threadripper is complete overkill for most developers and hella expensive especially at the top end. May also not even be that much faster for many work-loads. The 9950X3D is the "normal top-end" CPU to buy for most people.
I'm not very enamoured with distcc style build farms (never seem to be as fast as one hopes and fall over a lot) or ccache (picks up stale components) so tend to make the single dev machine about as fast as one can manage, but getting good results out of caching or distribution would be more cash-efficient.