Updated with word from the David himself:
You wanna make sure it’s not a seized camshaft. If it’s truly just a timing chain, then it can be done fairly easily.
I genuinely have no idea whether this is something I could fix, but I do (in normal times) have mechanics to fall back on. Given that I have no tools and no skills, is this something I’d have to give to an expert?
It’s practically next door and for $850 I’m sorely tempted.