Hi Luca,

You have two options:

1. You can learn how to use new SPPB 4.0.x - also by reading its documenation >> https://www.joomshaper.com/documentation/sp-page-builder/sp-page-builder-4/first-look
2. Or you can recover website from backup, if you don't have it, ask hosting support for it.

SPPB 3.8 will be supported for next 2 years, so you have a lots of time. Do not fight with problems, recover site or if you didn't edit any page, you can still reinstall with SPPB Pro 3.8.8 package.

No, every link (Get started, create a new page, settings, ....) redirect me to the frontend and to my user account, so i can't do anything

so do what I wrote above.

So your answer is: install the new version, but if you encounter a problem unistall and use the old one? Good support, it sounds like: we don't care

Do not be surprised if people download your extension illegally

It means that that version still needs updates, it's possible that on 5% cases something may goes wrong.

They always does, starting with Windows, Games, Graphic software .... probably even you have "illegal" music/video on your laptop.

You should investigate the 5% of cases going wrong, they're customers too.

You don't even asked me what Joomla version, php version or sort of: how can you improve your extension if you don't investigate the issues?

I will back to the 3.8.8 version, you know...i pay peanuts

I offered you a solution that will save you time / nerves, if you absolutely want to play with the new version do it on a test subdomain, not production one. Install clean Joomla + SPPB 4.0.x but maybe wait for 4.0.4 / 4.0.5 version at least. Honest advice from somebody who knows better this time.