I’ve been lurking on this topic for a while, and I think I finally have an answer.
Most of the time, I find myself, watching a stream on Twitch of a speedrunner playing a game (Usually a Tony Hawk game) on my CRT monitor, and if said stream has no music, I stick a mixtape in my cassette deck that’s attached to my PC via USB. (Or even a record if I have one on me at the time)
On my main LCD monitor, I like to play about with learning an SDK for some obscure retro console, or just chatting to friends on XMPP, Matrix or Discord, usually about languages or retro gaming.