I thought that everything was already displayed there, but in the end I found out that this part of the form (HTML Block for the dropdown) is still missing.
Please deactivate all the plugins not related to the theme and switch the parent theme, check the issue, If the problem has gone, activate the plugins one by one, checking the issue to detect which one causes the problem.
Please contact your host support and aks them to increase this parameter PHP max input vars: to 5000 min, now it is 3000