I will dump a bunch of links on you, since i have played with Archer A7 v5 (same hardware as C7 v5) to understand it's bandwidth limitations. Being a single CPU router, CPU irq handling is the limiting factor.
See:
- Archer A7 v5 wifi throughput test results using iperf
- Comparative Throughput Testing Including NAT, SQM, WireGuard, and OpenVPN - this whole thread is a great resource
- Test with alternative "ct-htt" firmware, ie:
opkg remove wpad-basic ath10k-firmware-qca988x-ct &&
opkg install wpad-openssl ath10k-firmware-qca988x-ct-htt