Following instructions are provided without any warranty, and may even get you in trouble legally. The instructions are provided for testing, learning, preventing e-waste, and should be use with care. We (including contributers + commentators) are not responsible for any damage to your device(s) or any legal issues.
Instructions have been moved to https://github.com/francoism90/asus-router. :)
Followed steps on a GT-AX6000 from Germany. Tx power did increase and better signal (signal strength from same spot -58dbm to -44dbm). New channels (149 and up) appeared as well. GUI changes seems to not cause issues and I can swap to other channels in GUI. However, whenever I try to connect to channel 149 from an Intel AX211 card, Windows shows I am using wifi 4 instead of wifi 6. Lower channels (36, 44, 48 etc) are fine. Is this an Intel issue like the previous posts indicated? Thanks for the help and good luck everyone.