you cannot change Boot order from Recalbox OS; raspi-config is not implemented.

all changes in config.txt file will be overwritten at next reboot.

you need to boot Raspberry OS on SD card to update firmware and modify Boot order with raspi-config

sudo apt update sudo apt full-upgrade

sudo rpi-eeprom-update

sudo raspi-config

Advanced Options --> Boot Order

SD Card Boot NVMe/USB Boot Network Boot

I am not sure you can boot USB before NVMe