Not really compressing it, just encoding in H265 10bit Intel or AV1 10bit STV.
This and just simply slashing on bitrate of vids, many of MMD artist just blow bitrate up to the sky and I just encode it at 15MB/s for 4K, 12MB/s for 1440p and 9MB/s for 1080p.
Sure, sometimes quality takes a small hit but to me, it's a worthy trade off.
Let's say, 3GB vid gets slashed down to ~500MB-800MB and looks nearly the same, so I call this a win.
Btw, I use Handbrake and just slash down bitrate, the rest is on handbrake itself.