This is unsurprising. They do this a lot with especially short usernames. I recently saw an interview with a German youtuber (@dima) where they talked about how youtube gave them this channel. In that case the channel still contained private videos and information of the previous owner, which I find somewhat shocking.

Easy fix: use youtube without a channel, e.g. using newpipe or yt-dlp.

> but my user handle is gone.

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.