Lets look at connmand as a service. Its not active on a headless server. Not sure if it is on a desktop build.
sudo systemctl status connman.service
This is where I got the Image
https://solaranzeige.de/phpBB3/viewtopic.php?t=4432
ok so lets run the following
sudo systemctl stop connman.service
once complete
sudo systemctl disable connman.service
then reboot and check again.
does the gui not start? or does it boot to the command line?
I no longer have access to Putty.
I'll reinstall the image
Apologies. I didnt anticipate that happening.
It's no problem, the imgae is installed straight away 
what else could I try?
There is still a service thats keeping that connman service on port 53. I'm trying to figure that out at the moment.
I found this How do I disable network manager permanently? - Ask Ubuntu
The solution mentions stopping and disabling 4 total services tied with network-manager.service.
Here you should disable NetworkManager service (as you have already done):
sudo systemctl stop NetworkManager.service sudo systemctl disable NetworkManager.serviceand three more services:
sudo systemctl stop NetworkManager-wait-online.service sudo systemctl disable NetworkManager-wait-online.service sudo systemctl stop NetworkManager-dispatcher.service sudo systemctl disable NetworkManager-dispatcher.service sudo systemctl stop network-manager.service sudo systemctl disable network-manager.serviceand then reboot.
keep in mind that each sudo command should be run seperately so 8 total commands. I'm not home so I can't test this but it should work. I don't think it will prevent your system from boot like the connman.service did.
I thought that would have done it. I'm going to do a test build on a spare pi and see if I can work it out.
I installed the standard raspberry pi bookworm with desktop and pihole without issue or having to disable the network manager so its something in that image from Solaranzeige that is different.
What does the following command show:
cat /etc/os-release
Also, I did a quick search for that system and pi and saw this article. I don't read German but the image in the article suggests a similar issue with connman service. It might give some insight.
https://solaranzeige.de/phpBB3/viewtopic.php?t=4548
I also found this article. It may also be a solution.
Look at section 3.5 It instructions you create a directory and add a config file to to that directory. Then either restart the service or reboot. Creating the directory and the file needs to be done using sudo.
sudo mkdir /etc/systemd/system/connman.service.d/
sudo nano /etc/systemd/system/connman.service.d/disable_dns_proxy.conf
paste in the following into the editor
[Service]
ExecStart=
ExecStart=/usr/bin/connmand -n --nodnsproxy
Then do a ctrl+x to save the file.
reboot and check the ports with:
sudo lsof -nP -iUDP
I would give the arch.wiki instructions a shot then. Create the directory and file and see if that helps. If not I'm not sure what else to try.
Thank you, I've already tried it, unfortunately it doesn't work either. Have you tried installing the solar display image?
I had to register to get access. I think I have the right version "Solaranzeige_V6.0.1-64Bit.zip"
I've downloaded it. I'm not home at the moment but I will test it and see and post results.
great, thank you very much
A search here for connman reveals below: