I too have made the transition from "full stack" (well, backend mainly) dev to systems (& embedded) over the last decade or so. I generally present myself as a "software generalist with a systems focus" -- I'm by no means a systems eng <i>expert</i>, but it's become my sometimes fanatical interest and I love working on "harder" CS and lower level problems. But TBH I'm seriously considering doing a bit of a voyage back into the backend of web-facing stuff.<p>And only because the job selection -- especially locally, (and remote is getting harder to find) -- is far far better. Even if the type of work isn't usually as interesting. 9/10 of the jobs out there are some variant of this.