If your device is rooted you can try this:
Change the file cfg_ane_lx1_hisi.ini or cfg_ane_lx2j_hisi.ini depend which model do you have.
This file is located in this path: /vendor/etc
Disable 5G doing this:
Then tell me if it work with you because I cannot run a test with mine because I don't have passwords for 5Ghz WiFi's around me.