I have the same issue after installing the fix (php 8, and joomla 3) and cannot create new forms or modify existing ones anymore. (Same result in the backend as shown in the print screen above. Any hint?
Please see print screen attached. (As mentioned in my first post, it seams to be the same issue as described at the beginning of this thread. I already went through all the steps that are described and could at least fix the content builder issue. Nevertheless, I still have troubles with adding or editing forms.)