I feel an analogous pain on the flip side of interviewing! I would kill for a job that lets me exercise some of these skills, rather than the brain rot of a typical software job which doesn't demand that one thinks too deeply about things.

I think the only way to do this might be founding your own company and building your own product in Forth and Lisp.

React re-rendering logic requires one to think plenty deep.

Of course, there's interesting work to be done at all levels of the stack. However, not every company will allocate time for solving frequently-encountered problems with creative solutions. Often, it's "ok, what's the minimum amount of time we can spend to fix this problem *right now*?", rather than "how can we make sure we don't have to re-solve this problem again ten more times in the future?"

Not me, but a friend described a whole team of engineers at his company hired to put out the fires caused by using database software that is a poor fit for the application, rather than biting the bullet and either 1) performing a migration or 2) rolling their own solution.

I wish my colleagues would appreciate the beauty of abstraction and PL theory as much as you do. It seems they actively resist any effort in that direction.