Many people have problems with MMS
And it is hard to know what to try
Surely there must be some kind of logging of the MMS communication?
I know that when I installed Lineage OS I had to set up the APN for Telenor manually (which was my provider then), for MMS to work. I think I found the settings online somewhere, but unfortunately I can’t remember where…
Edit: a quick googling came up with this: https://www.teleproffs.se/support/knowledgebase/apn-installningar/
Those settings could very well be the ones I used.