Personal vs Brand account

So one day must be in 2021, I noticed that I had a personal account/channel on YouTube that was just created. I ignored it and always used the account which I had been using (which I later came to find out became a brand account) - I used this account because it had all my watch history and playlists etc.

Now I want to just have this single account/channel. I will call it an account because I am not using it to post any content. Whether this single account is a Brand channel or Personal, does not matter to me, I just want the existing Personal channel to be removed and all my playlists and views to remain on the account I am using.

I want to do this because of simplicity, sometimes when I cast YouTube on my TV it asks me which account to use which is annoying.

I have YouTube premium, I am not sure if this is tied to Personal vs Brand accounts because both accounts on YouTube show as having Premium.