Times are tough at the moment (cozzie livs), but as developers we've got a unique set of skills which are in high-demand, if you know where to look!
Engagement-based earnings are where you'll receive a share of revenue, based on the amount of time a user has spent on your site, profile or consuming your content. It's typically a small amount, at least for smaller sites or creators, but adds up over time, and anyone can enable this- so you've got nothing to lose.
I personally signed up for Brave Rewards a couple of years ago. And after verifying ownership of my domains + profiles, I've consistently been making a couple of quid a month - about £200+ so far (despite being a Firefox user!). It's not much, but for very little effort, it's worth it.
For more info on how this works, take a look at the webmonetization.org spec, a proposal which makes use of payment pointers via ILP to stream income from WM-enabled visitors, via the use of a simple <link rel="monetization" href="your-pointer-here" /> tag.