Archer C6U very slow wifi

I've been using TP-Link Archer C6U v1 with openWRT for a few months now and it seemd to work great until I decided to buy another one to also install openWRT on it and just out of curiosity I decided to compare wifi speed on stock firmware with the one I got from openWRT one and it was significently faster on the stock firmware. Any suggestion on how to fix wireless performance on this router for openwrt

It's rather moot to discuss this, without absolute figures pointing out the throughput delta for both test cases.

Okay I should have mentioned that the same phone got around 18 Mbit on openwrt and around 380 Mbit on stock on the same connection with routers at exactly the same spot ( not running at the same time to avoid interference)

please upgrade to 21.02.1 and test wifi speed on 2.4 and 5 ghz band separate, with iperf3 or android app WifiSweetspots.

Question: has somebody tried to extract the boardfiles from the C6U vendor firmware and put them into the appropriate /lib/firmware/ path yet? (make sure to remove the board-2.bin before loading ath10k_pci)

Well I don't know if any one has but since I have two of these and am willing to potentially fup one of them if you tell me what you mean I can try doing it

Do you have a helpful resources on how to do that

I just want to know if is wifi performance good to daily usage,like capable transfering about 500Mbit/s on 5ghz band or what kind of speed limit?