The biggest hurdle for users today is that They have shifted all focus to the Affinity suite (Publisher, Photo, Designer). Consequently, you cannot simply log into a modern "My Account" portal to retrieve your old key as you would with Adobe or Microsoft.
Caution: Only for advanced users. If PagePlus X9 is currently installed on an old Windows PC but you can’t see the key, you can sometimes retrieve it from the Windows Registry: pageplus x9 product key