Class "RegularLabs\Plugin\System\Modals\Params"...

I have updated your applications in Joomla 4 (updated) and now I can't access anything.

--- 15 minutes later ---

I was able to solve it by deleting the folders:

/plugins/system/regularlabs
/libraries/regularlabs

Then I was able to enter the Joomla panel and uninstalled all the RegularLabs applications.

I have reinstalled the "Extension manager" application and reinstalled everything I needed and it works again.

The bug blocked Joomla completely.

What a scare.

The update made me lose all the position conditions of the modules. I tried reinstalling and the site crashed. I disabled all regularlabs from the db and deleted the packages from admin. I tried reinstalling Advanced module manager and the conditions didn't work. I downgraded to v.9.90 and it works.
Joomla 4.3.4 all extension updates

Same problem here . About 6 sites are down with error "Class "RegularLabs\Plugin\Syste​m\Modals\Params" not found" after updating of Regular Labs extensions. 60 sites more to go, but I fear that there will be more problems...

UPDATE: was writing the message below, while you replied on this thread...

The strange this is that on the websites that got corrupted, the "modals" is not in the list of installed extensions ( in "manage extensions" I selected type "package" and searched for "Regular". So I don't think that the Modals-extension is used (might be used before and uninstalled later. Don't remember). In a particular site only these are installed:

Regular Labs - Advanced Module Manager
Regular Labs - Articles Anywhere
Regular Labs - Better Frontend Link
Regular Labs - Conditional content
Regular Labs - Conditions
Regular Labs - Extension manager
Regular Labs - keyboard Shortcuts
Regular Labs - Library
Regular Labs - Modules anywhere

I have used the solution by César Martíne to get the websites back again.

I've also updated modals and site already admin part don't work anymore. How can I get this working again

Thanks. It is not necessary to uninstall RL-extensions?