Happens to me constantly on the P6P. Rebooting phone fixes it. Absolutely hate this bug
You can import YouTube subscriptions by clicking on the Sources tab and then tapping on the YouTube source (says tap to open in small print). You can then sign in and after that you'll have import subscriptions as well as import playlists buttons.
If my STI died tomorrow it's getting a built block haha. That car is staying with me to the grave
It's important to know what's going on when the computer cuts power. I had this start happening to me when I was playing VR games. I had been using the same hardware to do so for a year beforehand, but it turns out I was just riding the limit of what the PSU could supply. When I actually took a look at how many watts the UPS was reporting it was happily under the PSU's rating, however Nvidia GPUs are known to power spike at times and draw way more power than they're supposed to. That's what was causing my issues. An upgraded PSU indeed fixed everything.
I preferred having alternate themes per account. A theme export / import should be the way to go here. Maybe a global theme setting with per-profile overrides would be nice but seems like more work than it's worth. Themes are usually set once and forgotten once people are happy with them