Dowlink in both channels is working mostly on 64QAM5/6 and 256QAM 3/4.
Uplink -64QAM 5/6. It means that at RSSI -55/57 dBm ( it is enough for 256QAM5/6) you have high interference , especially in UL.
So channels are not clean.
Are you sure that test traffic passed via two channels? It seems in test only one 40 MHz channel is used.
Please, begin to test with only one channel 40 MHz. Choose channel, that gives you 97%-100% UL and DL 256QAM 5/6 modulation. Use CA to find clear channel.
Please show UDP/TCP test traffic in BW MT windows, not only traffic at ethernet MT. Jitter is growing when wireless interface is overloaded. Your traffic is not smooth and latency jumps when traffic jumps and exceeds throughput capacity.
Please look at https://community.cambiumnetworks.com/t5/PTP-Stories/PTP550-Field-Test-12-km-2x80MHz/m-p/102604#M341 how PTP550 test should be done properly.