Worse, the app still showed my username for a long time meanwhile youtube.com/@Switzerland already showed that of swiss tourism (Schweiz Tourismus) and I was not aware of that. Hence, I lost it some months ago.
Why do I tell you? You might loose your username and you aren't even aware of it.
Easy fix: use youtube without a channel, e.g. using newpipe or yt-dlp.
Did you ever have it? When they introduced handles you had to specifically claim that name, otherwise you get @(name)-(random), it doesn't matter if you had /Switzerland as a channel url.