Basically nothing. I tend to keep my work computer only for work. Once in awhile I might use it for looking at forums or the news, but I mostly use my personal phone for that.

Work for work.
Personal for personal.
This is the way.

Just vogons and ebay. "quiet" web pages that I can flick to when I have a spare 5 minutes.
I hate watching work related YouTube videos at my desk let alone personal stuff.

Even though I'm in the I.T. Dept our computers get the same policies applied as rest of the company.
So while it may come up in a report as a "risky device" for some legit reason, would still prefer not to be flagged at all

work computer stays clean. only for work.

BUUUUUUUTTTT.... I do have an old laptop next to it for the sole purpose of discord/ youtube /lurking on vogons for anyone that mentions Pentium Pro...

It's difficult to do things for me there, just wrong environment. I look at forums sometimes when there's a break from annoying customers. The computer I have there is free from chains of corporate group policies though, which is awesome!

I bring my own device to work, as it's easier to make sure I have a workstation, and dont have to fight my coworkers for access to one.

There are slow periods some nights where I will play a casual game, like rimworld or cultist simulator, but typically it's all business at work.

Before the age of smartphones, I could understand using the work computer to occasionally catch up on the news, browse forums or watch a funny YouTube video.

But nowadays, just use your personal phone or tablet (with its own internet connection) for that stuff. Especially if you're in a corporate environment, with strictly regulated workstations and logged internet traffic. No reason to use a work computer for any non-work related stuff.