To restore your exact settings: If you didn't make any changes to your plugins' configuration nor install any new plugins since your last backup (or can redo the changes you made), you can just restore the content of your
#__comprofiler_plugin MySQL table from your last backup.
I'm deeply sorry for that bug, that was entirely my fault, and for which I take full responsibility.
It was due to a temporary line of Joomla 4-bug-hunting-code
Code:
$plugin->params = ""
forgotten in the installer after implementing one of the Joomla 4 database compatibility features (a default value for params was missing in that table structure, that Joomla 4 detected). It was also an issue in my Joomla 3 testing. We have already fixed that issue, but we will not release another nightly before we do some thorough re-testing. We will also revise to improve our testing procedures, as we missed a warning that we should have seen regarding this bug.