Problem/Misunderstanding Business Forms - Form Elements Type "Read-only"

Grafana v11.0.0
Plugins
Business Forms v4.6.0
Business Table v1.4.0
Datasource PostgreSQL

Hello community,

I use the ingenious business plugins to edit a table from Grafana. This table contains applications that are/will be set to maintenance mode.
An index is written, an import time, a flag (enabled/disabled) and, of course, the start and end time.
I use this table to view the applications in a dashboard.
This works very well.
To create a new entry, I use the Business Forms.
Here is an example…

And now to my problem:
I retrieve the import time in a query.

However, I was only able to transfer the value using the form element type ‘Select with custom options’. I simply specify the query as the option source.
But since I only have one value, I don’t actually need a select.
And I tried it with the type ‘Read-only’. Here, too, you can specify a query as the option source. However, this read variable is always empty.

Can I solve this with a different form element type?
Or did I not understand the read-only type correctly?

Jo