Battery usage seems to be back to normal, after a day with some text messages and about an hour of media player usage to play music it’s 30% down, which seems normal to me. Mcetool shows 91671 for uptime, 85362 fpr suspend time.
Could it be that the firewall rule also caused the battery issue? It also blocked loopback traffic which is often used for inter-process communication.
/proc/last_kmsg doesn’t exist, so there is no info there. The crashes seem to be triggered a lot by typing on the on-screen keyboard, for example when using the terminal or writing a text message, often when i type a few characters quickly after eachother, for example when typing in the terminal and you place your finger on a place where you touch multiple letters at the same time.