Hello everyone can any one explain me please how to set up 5g wifi signal from the range of 149-165channel cz my router not showing more than128 and DFS 140max 20/40/80/160

I bought the router archer ax55 in saudi arabia and there it's was woring normally very in 5g wifi signal , but now i came to Bangladesh its not showing to my phone,,, only 2.4ghz working , when i turn o. Airplane mood its workin well

Please can someone help me 

Router V.1