Poor wifi quality on Realtek 8821CE Wireless LAN 802.11ac PCI-E NIC and with 802.11d enabled

I have a network with CapsMan, and it's been working without any problems so far.

Recently, the salespeople replaced a Dell laptop with an 802.11d problem with a Realtek 8821CE Wireless LAN 802.11ac PCI-E card. And the Wi-Fi problems started happening in these laptops. The laptops either didn't recognize the Wi-Fi at all or the connection performance was very slow.

I noticed that disabling 802.11d significantly improves the connection performance.

Is there anything I can change in the CapsMan or AP settings to prevent this problem?

Maybe you set the wrong country?