Voicemail notifications

I just upgraded from the S22 Ultra to S26 Ultra. I have used Youmail, and never once used the T-Mobile option, for my voicemails since I had a Note 7 with no issues. It's always easily redirected them to their service and the T-Mobile one has never tried to still work. All of a sudden with this new phone I am constantly getting a notification from phone services that just says "T-Mobile voicemail." I've never ever gotten this before. I've verified multiple times that Youmail is indeed working, but I cannot find a way to stop these annoying notifications from popping up multiple times/day. When searching here, and online, I can only find stuff about turning off text message transcripts, changing the greeting, flat out blocking voicemails, or similar. I'm worried that I'll miss an important voicemail if it goes to the T-Mobile one by chance and not Youmail. Not to mention the constant notifications are driving me mad, and I cannot turn off "allow notifications."

Does anyone know what I can do to stop them that won't also disable voicemails completely?