Just noticed this channel https://www.youtube.com/c/alldemos/

which has a bunch of old ass demos being uploaded in really nice high quality. It's fun to browse. Not just Quake but old UT stuff too.

heres some recent uploads

Shub vs. DOOMer, bo3 (XSi 2000, LB 1st round) Shub's only Q3 demo - https://www.youtube.com/watch?v=6qyTau6nDuQ

Fatal1ty vs. Immortal (XSi 2000, group stage), bo3 4K -

(UT2003) ESWC 2003: Fatal1ty vs. Lotus, bo3 (Bronze final) 2K - https://www.youtube.com/watch?v=ltqb4wf6OPg