Do you have any recommendations on how best to sell yourself from such a position? I have a significant C99-era/close-to-the-assembly fundamentals background, but I see a lot of “if you haven't already AWS'd all the AWS at your last company in production at scale, then there's someone behind you who has”, and that kind of thing has both been a notable lacuna in my experience and something that's notably less fixable independently than e.g. “plow through a React tutorial to familiarize yourself with the basics”. In particular, it seems like in the heavily external-service-integrating style of development, a lot of experience comes in along the lines of “remembering the pitfalls you ran into with particular vendors under particular loads” and the fundamentals don't get you as far. But I hear a lot of conflicting things about this.
I'm someone who's (supposedly) quite good underneath but has stagnated a lot over the last few years (and on and off before that, sadly) as other issues drained away my ability to work. I'm gradually stabilizing things and trying to find the best way to maneuver, and I'm pretty worried that everything's going to pass me by because my experience isn't of the right kind and I'm not legible enough. The people who are getting the jobs with all the traits I want are the ones who got a Real (that is, close to culturally archetypical) Job in 2018 and did their time in the salt mines with the three verifiable contiguous recent years of experience.
If what you say is true, then it's possible what I mostly have is a marketing problem, and it may be that e.g. some of the “actual demonstration of ability” is more readily solvable with “pull some stuff out into public repositories and freshen it up” than I've been imagining.