Ok, the rev3 board came today and i did some measurements and its now connected to a rak, solar panel and battery.
I will do tests over the next couple of days to see if the rak wakes up again after the battery runs flat, if battery is actually charging etc.
Its the first batch of tests, since currently the battery also has a bms and the panel has a boost converter to 5v. But without the board, it never came back with those components before.
Anyhow, i also now made my github repo public:
It contains rev1 (@michimartini pcb), rev2 and the now build and in testing rev3.