The only supported way to disable updates is via group policy. Tampering with app components may break it. Generally you don’t have much leeway to use old app version as it won’t work on newer OS.
I don't have telemetry, but 70% of users are on 3.7.11 and haven't seen green line. Some who do dislike it. It's not my intention to spill sarcasm on feedback.
That's strange, that was fixed like 5 updates ago. I can't repro that and there's nothing specific to the taskbar position
Define later. 10000 songs later?
The change is intended (as all tabbed apps do have suffix and purpose of app is not to change new UX nor to break accessibility). No, I will not add checkboxes, sorry.