If your setup allows you to be a productive member of society, you’re golden mental health wise. /s

You may want to get your eyes checked if watching HD video on a tiny screen seems preferable unless all your content fits your displays native resolution; I am fairly certain my eyes are terrible. Maybe that’s why I love that dark themes are becoming more popular.

Transparency is nice, but Windows Vista is partially what converted me to Linux. I dislike rounded corners too, since content is always rectangular.

I don’t know why no mainstream desktop OS really has a good mouse driven tiling setup out of the box. I have a dual screen setup, so I mostly just full screen apps and alt tab if needed which reduces distraction. If I’m trying to focus on a single thing, the second screen gets turned off.

I find myself becoming more minimalist over time as well. Society seems to be more distraction driven by the day, so having an OS that stays out of the way is a boon.

The only option I can think of would be to use a vm. Unless all your apps support restoring sessions, I don’t think there’s any mechanism to do so globally. Getting stuff to start automatically or as a group using a script is easy enough, but that’s less than half your problem as you’ve described it.