I don’t think that SS reports properly, so I wouldn’t worry about that. I think for some regions that the default configuration only uses 5Ghz.
Good news, we are getting closer
Have a look at CountryRegionABand, and adjust it to match your router. Here are the possible values:
0: use 36, 40, 44, 48, 52, 56, 60, 64, 149, 153, 157, 161, 165 Channel
1: use 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140 Channel
2: use 36, 40, 44, 48, 52, 56, 60, 64 Channel
3: use 52, 56, 60, 64, 149, 153, 157, 161 Channel
4: use 149, 153, 157, 161, 165 Channel
5: use 149, 153, 157, 161 Channel
6: use 36, 40, 44, 48 Channel
7: use 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 149, 153, 157,
8: use 52, 56, 60, 64 Channel
9: use 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 132, 136, 140, 149, 153, 157, 161, 165 Channel
10: use 36, 40, 44, 48, 149, 153, 157, 161, 165 Channel
11: use 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 149, 153, 157, 161 Channel
Also since you can now ssh into the Pi, run iwconfig and make sure you are connected at 433.5Mbs.