Keep in mind you are still likely bound by an expansive intellectual property clause in your employment contract that says the company owns all work you do, even outside normal business hours.
If I could be paid to browse HN and make my un-sellable software synths and path tracers all day I’d be as happy as can be. Even if I could theoretically work on something I could sell, I’d probably rather write something fun than something useful if food on the table was already secured.
Ignoring the creative work you mention, I do have some experience with browsing. Prior to my retirement, I read RSS feeds for maybe an hour a day and Hacker News for an additional 15 minutes. After 2 years of retirement, I probably still spend an hour a day on RSS feeds but Hacker News has expanded to an hour a day. I didn't expect to enjoy HN so much given the opportunity.
It's pretty obvious that your employer owns work you do for your employer, and things you do on company time or using company equipment. But this "they own everything you do forever even at 2AM at home using your own computer" meme gets repeated all the time and it's complete bullshit regardless of what's actually in your employment contract. And this ignores the fact that the vast majority of employees in the US don't have employment contracts at all and/or live in states that explicitly make these broad types of IP assignment clauses illegal or at least unenforceable.
non competes are not enforceable in california and a few other US states iirc, although if there were to ever be an IP lawsuit, it would be a war of attrition (with odds highly stacked against the engineer)
