Probably Sectograph. I’ve used it for a couple years and I like it a lot. You can even have it on your smart watch.

The point is that GMT isn’t changing, the region is switching to an entirely different time zone, BST (British Summer Time). If your time is based on GMT, it won’t change due to British daylight saving time because GMT never changes.

For a similar example, in the part of the US that uses Mountain Time, states observe MST (Mountain Standard Time) in the winter, and most switch to MDT (Mountain Daylight Time) in the summer. However, Arizona doesn’t observe daylight saving time, so they remain on MST. MST always stays the same (GMT-7), the time is only changing because the states are observing a different time zone. The same happens with GMT and BST, it’s just harder to see because you can’t pick out areas that remain on GMT all year.

Yes, although I recommend against using /c/ because it doesn’t actually link to the community. I also recommend against typing out the full URL (e.g. https://lemmy.ml/c/asklemmy) because it might cause issues for people in different instances.

The proper way to link to a community is !communityname@domainname.tld. For example, !asklemmy@lemmy.ml

This may not be exactly what you’re looking for but have you considered using Firefox containers, automatically logging in to a different Google account for each container? I’m fairly sure this would work on mobile (probably only Android though), and is almost certainly more convenient and polished than a separate YouTube client.