If you set the “country” setting on the wireless interface to your country, frequency-mode to “regulatory-domain” and “antenna-gain” to the gain (in dBi), power output should be limited to what’s allowed where you are.
Note that increasing transmit power (“txpower”) doesn’t necessarily mean a better range – the limiting factor tends to be the connected devices (phones have very small antennas, for instance) – and most laptops won’t increase their txpower beyond what’s allowed in your country.
For the 5GHz band, don’t forget to also turn on radar detection if you’re using a frequency that requires it.