Thanks, much better. I can't see any obvious signs of problems, or leaks. The service boiler is filled via a single solenoid that opens the way to the service boiler when it needs filling. e,g, the pump always pumps to the brew group, but there is a T junction which leads to the service boiler that's usually closed. When the service boiler wants water that T junction is opened and water continues to the brew group and now also to the service boiler..
So a couple of tests you can do, with the machine OFF, remove the wire identified below, switch the machine on for 5-10 seconds…what happens? Switch the machine OFF then put the wire back.

Only if the pump ran in the previous test. is leave the top off, switch the machine on and make a video of what's happening (basically of the display). Just 2 or 3 minutes should be enough. Post that video on YT as unlisted and then paste the link here.