Switching between different stacks (paid work vs. work I 'have to do')?

What is the best advice you have for someone coming back into a part of the stack they don't focus on primarily for their paid work and how much time should they spend on doing it regularly everyday vs. their actual other work that actually compensates them?

For example, I get paid to do work in AI, games, native iOS apps, but I spend too much time on web dev, which I left ages ago (so rusty), but do it for necessity (ex. working on portfolio projects, marketing websites for personal/professional brand).

Maker vs Manager Schedule - and Divvying up parts

I find that swapping between two different code bases, different projects, different languages, or different parts of the stack is too taxing - multitasking not being effective).

I've tried to resort to blocking off parts of my calendar with harder deadlines for doing web vs. iOS mobile, AI etc. meaning I should prioritize more of my iOS mobile and AI development instead of web development. Web development can derail my progress on things I actually need to get done.

And ya, I want to avoid being called 'full stack' developer/engineer (hate this term with a passion since I often find none of these people do front-end, which I did for a long time or UI engineering, and it's a catch-all for back-end development that isn't say AI, or even necessarily a data engineer/dev ops). But I find that maybe some of these folks might understand this kind of similar problem/relate?