The "fun" part of being a frontend dev who naturally gets pushed into fullstack as part of the realities of the job is I have to keep on top of developments in CSS, UI frameworks, Typescript, Vue, testing frameworks, Ruby, Rails, etc. Not to mention the build tooling (Vite/webpack) and deployment / operating system stuff. Fortunately the database stuff rarely changes with Postgres.

I wish I could specialize on any one of these sometimes...but such is life at a startup. It's more interesting being able to do them all anyway and be able to build entire apps yourself. Just occasionally frustrating.