YouTube is facing issues at the moment, so just get a coffee and wait for some time.
Feed -> Subscriptions -> "+" icon at the top
Press the three dot menu -> Settings -> Instances -> Select a different instance.
Which instance you choose is up to you, a list of them and their locations can be found at https://github.com/TeamPiped/Piped/wiki/Instances.
Even if an instance is responding quick for some time, it's not guaranteed it's also stable and has enough capacity to handle all the traffic.
That's not an issue an update would solve, I assume you're using the app with an account and the instance you use just has been down for some time?
There's also https://status.piped.video which allows you to view the uptimes of all public instances, and their might be added something like that to the instances api in the future too.
This has been fixed in https://github.com/libre-tube/LibreTube/pull/4736. (Not sure if you're the person that submitted the issue or someone else did.)
Yes, that's a dependency of the relm4 crate we're using, I haven't yet figured out if we can disable it. The app doesn't use any libadwaita component though.
Requested here: https://programming.dev/post/320260. Please upvote it in order to become considered as a new community on programming.dev :)
Yes, I don't want to move the project to libadwaita either because I dislike its flat design and don't use the GNOME environment in general. And I love theming Gtk apps :)
Not yet, but it would indeed be a good idea :) I created a request for a community here: https://programming.dev/post/320260. Not exactly sure if that fits programming.dev, we'll see :)
Server Adaptive Bitrate Streaming, see https://github.com/LuanRT/googlevideo/blob/main/src/core/ServerAbrStream.ts. It's a format Google developed to be used by YouTube internally, there's no other service that uses it and thus it's also not supported by any player libraries.