Shortly the problem: after the update to Types 3.0 I don't see any of my custom fields in the Toolset settings "Custom fields".
"Here I see no created fields in your install. Did you create Fields during the Beta releases? Could you add as many steps you can recall to the new ticket so we can handle this as soon and effectively as possible?"
There was a lot of custom fields created with the previous versions of the plugin at different times (it's a continious development started in 2016, last fields were added a couple of months ago). I never used Beta versions on this site.
You can still see them if you open any custom post for editing in the admin, they are all there, but not in the settings.
I deactivated all the plugins except the ones of Toolset, it's still the same.