It didn't disapear even when installing this addon and then uninstalling it again.
All that happened for me was that I then had 2 amazon assistants for a while.
so went into
C:\Users\UserName\AppData\Local\Programs\Opera GX\76.0.4017.208\resources
Deleted the promo thingy and then the bloatware was gone for me

(Granted I still have this addon installed with the only permission to change the page no.page.existshere
and it is disabled)