Though note you can define your own "Virtual File System" (VFS) for SQLite to use[1]. It might be a bit of an undertaking, but I think you could use that to run on just about anything with storage you control. (I haven't done it myself, just some research back in the day)
Saddly, bad middle manager wants to hire a yesman (or women). Not an experienced engineer that will challenge them by highlighting to upper management the project technical debt, the lack of tests or the broken CD pipeline.
Possibly they might like a tactful experienced engineer who's careful not to make them look bad to senior management, but quietly fixes some of the more glaring issues and makes the whole team look good? The trick I guess is showing in a job application that you will behave like that.
"Not an experienced engineer that will challenge them by highlighting to upper management the project technical debt, the lack of tests or the broken CD pipeline"
So... everywhere? Haha the tests are always garbage.
Same. I've had interviews where people (younger than me) tell me "how do I know you won't be bored doing level-10 work, while your skills are clearly level-30 work? I don't want you to debate my budget or strategy" (because the team FTE costs is $2-3m and I'll be one of the pawns, while I've ran $20m teams as a rook or king).
Frankly no one wants to hire an engineer who highlights technical debt or a lack of tests without being asked for it. This kind of negative people is annoying and IMHO is indeed a reason why employers hesitate to employ older employees. Many are a pain in the... (and I say that as someone who's turning grey as well)
Most employers want to hire someone who actively improves things, someone who solves issues, and not someone who just complaints about them and makes demands.
Seeing and raising red flags as and when they arise--or even better, even before they arise--is the hallmark of a good employee. If you don't want to hire one such, good luck. That said, there's a difference between flagging and nagging. Again, a good one will know the difference.
I whish there was more ressource to learn this "low-level" approached to web developpement.