Today I rebuild from scratch one of my websites, using Joomla 4.2.8.
I have a Lifetime subscription, so I downloaded Extension Manager, I created a new key for this brand new site (successfully loaded), and then installed Content Templater by Extension Manager.
Unfortunately, Extension Manager says that I have just the Free version o Content Temlpater. No way to force it to recognize the Pro version.
So I uninstalled Content Templater, downloaded it from you site (the Pro version) and installed it again using the normal procedure of Joomla.
No Extension Manager knows I have the Pro version.
The problem is over, but it's quite annoying, isn't it?
PS: my English is no so good as it is meant to be. Forgive me!
After entering the Download Key in the Regular Labs Extension Manager, it should offer you the possibility to download the Pro versions.
If it doesn't, either there is something wrong with the Download Key, or some sort of caching is getting in the way.