32Km link BW issues

I’m setting up my radio link for 32km and I’m having BW issues.
Only getting 300Mbps download / 50Mbps upload (from AP side).
Using two C5c.

If I go to a frequency range from 5000-5600, I only get few Mbps.
Only on 5800-5900 range I can get 300Mbps (I need more, near 500 Mbps).

Also frequencies from 4000-5000 doesn’t work. Station never connects.

Access Point


Also, I cannot get better than -58dBm signal