I don't know if there was every a way to remove the messengers section permanently, but they absolutely need to add this. It's very annoying that regardless of how many times I hide/remove the messengers, they keep returning over and over again.
It's almost daily now.
I suspect they're getting paid by Meta to persistently push Whatsapp and Facebook Messenger. If this continues, I don't know if I'll keep using Opera. Might have to switch to Brave as my primary browser.