I bought Nova 15+ years ago and now don't know where my activation code is

I've had Nova Launcher pretty much ever since it was first released. Decided to buy it about 15+ years ago.

I've now just started randomly getting ads on my apps screen. I've also started getting random ones elsewhere and it looks like this is due to a change of owner in Nova Launcher.

So I went into my settings and apparently I need to upgrade to Nova Launcher Prime, which I did over a decade ago, and it wants me to Activate a Direct License from Google Play? I'm pretty sure way back then I bought it directly from the website.

How can I go about (re)activating my Nova Prime?