Except for video transcoding, a PeerTube instance is not CPU bound. Neither Nginx, PeerTube itself, PostgreSQL nor Redis require a lot of computing power. If it were only for those, one could easily get by with just one thread/vCPU.
Framasoft will therefore takes the time to improve the software progressively, at its own pace and with its atypical methods which, so far, have proven to be rather effective.