So after upgrading from Ubuntu 18.04 LTS to 20.04 both Arduino IDE and Arduino Pro gives me:
"exec: "python": executable file not found in $PATH
Error compiling for board ESP32 Wrover Module" - same with all ESP32.

Tried reinstalling, currently on 1.8.11.
Read for two days and tried tons of different things, including guide:
https://github.com/espressif/arduino-esp32/blob/master/docs/arduino-ide/debian_ubuntu.md
https://github.com/espressif/arduino-esp32/blob/master/docs/arduino-ide/boards_manager.md

Python3 and bunch others installed.

Nothing helps...