There has been some development since then,though. For the last week, I could have the computer on and use it only for not demanding work, and if it was fully charged, it would keep on charging, while the computer was on. For, say,streaming films and such, it would start blinking, indicating, that it
wasn't charging. I then had to turn off the computer, and charge it up.
It was like that until yesterday - then it began to be possible also to do streaming, without it starting blinking, and at the end of last
night it was charging fully normally, and I could use the computer without limitations and still be charging it up. while doing so.
It is confusing, but I'm of course very happy about this development.
So for now it seems, my problems are over.
If anything changes in the next couple of days, I'll post.