Lightroom Classic: 11.2 on macOS 12.3.1
When I go to the site I can't purchase the product, what could be the problem?
when you click the "buy" button, it redirects the creative cloud to the welcome page
Well, subscriptions to Adobe products are done through Creative Cloud which you'll download along with Lightroom:
that's just the point that I can not buy a subscription there
Download, install, now try.
Did you go to:
And select/pay for a plan?
Typically a Photography Plan.
After you have a subscription, then download and install the Adobe Creative Cloud Desktop App:
Then use that to install, authenticate, and activate the apps.