Bootloop / No charging Logo - 2101-0001 with new battery

I have a defect switch with some strange behaviors where I do not know what could be defect.
First the switch was not charging at all - so looked that the fuse was not working which I changed.
There was also a short at the BQ which I changed also.

After changing Fuse and BQ there was some life back and switch loads with 0.41A which looked promising.
After putting together the switch I have seen that no battery symbol was shown on lcd - also switch was not booting into fast charge mode.
I changed the battery and was surprised that switch booted - a bit - so after Nintendo Logo if runs into 2101-0001 error.

After that I replaced the M92T36 and also the PI3USB chip - with no change.

Using the ‘old’ battey the ampmeter always jumps from 0.39a to 0.41a and back - with no battery symbol and also never going into fast mode - so seems that the battery is not charging.

Not suer if I must give up the repair for that switch or if someone have an tip what could cause this issue…