Hi friend.
Are you referring to the Regulatory Domain setting of WLAN Advanced Configuration in the following figure?

Generally, you only need to select the country or region where the user is located.
If you want to increase Wi-Fi access rate and coverage, you can try the following methods:
1. Avoid channel interference. To maximize the utilization of frequency band resources, 1, 6, and 11 can be used. 2, 7, 12; Channels 3, 8, and 13 that do not interfere with each other are used for wireless coverage.
2. Make use of antenna polarity.
3. Eliminate the wireless interference source. Common home interference sources are as follows:
Microwave ovens: Most microwave ovens work on the 2.4 GHz frequency band. The power of home microwave ovens is far greater than that of Wi-Fi products. Even if the microwave ovens are shielded well, Wi-Fi is greatly affected.
2.4 GHz cordless phone: Currently, the power of a typical 2.4 GHz cordless phone base is 9 V DC/350 mA, and the power is about 3 W. However, the power of Wi-Fi products is less than 0.1 W. It is recommended that Wi-Fi devices be deployed far away from the base of the cordless phone.
Wi-Fi interference: There are usually other wireless terminals in the surrounding environment, and these terminals may cover all channels. In this environment, Wi-Fi performance cannot be optimal. Use a network tool to check the status and signal strength of each Wi-Fi signal AP. Select a channel with less interference as the working channel according to method 1.
I hope I can help you.