Your experience with UNIX isn't worthless, but it's worthless to anyone who's working "further up the stack" than you. If you feel like your skills are degrading then you need to find a job somewhere that's actually building infra that shops will build on top of. Your skills aren't day-to-day anymore and that's a good thing. Your generation made all that junk turnkey in the way that you probably think about dealing with Ethernet frames. Taking my first AWS job literally obsoleted all my system's knowledge -- super humbling experience -- it wasn't completely worthless but none of the problems I've spent years working out solutions even existed anymore.
You're confusing people building products with people building infrastructure -- the devops role makes this messy because you're usually "using" infra tools like a dev rather than building them. If you're working on foundational elements then literally nothing has changed. If you're shipping products then absolutely retool around a cloud provider, the infra isn't your secret sauce and if you have to move back on prem because of cost it will be good problems to have.
I mean this completely sincerely, take a job at a company that's providing hosting/services to people. All the old timers with deep deep systems knowledge are gods.