802.11NAC Wireless performance bad after 21.02 upgrade

[stack]

I've had this same wireless setup for months without issue - one SSID for the 802.11bgn (only N active) radio and one SSID for the 802.11nac radio.

I noticed after the update to 21.02 that my 802.11nac range dropped significantly. I used to get wireless at 5Ghz NAC almost to the edge of my property, but right after the update I could barely get connection outside of my house. That's fine. As long as connection inside the house is good, right? Well, that isn't the case. The floor with the router connection is stable and great but the floor above the connection will drop or the device says it is getting signal but won't actually connect - weird things like that... sometimes. The fact that it isn't repeatable but regularly flakes out on me is weird.

However, the 802.11bgn connection is fantastic. Still great range, solid connection, ect. Just no where the same bandwidth performance.

Anyone have any idea what is going on?

Thanks.
Here's more details of my setup:

Model: TP-Link Archer C7 v4
Current firmware: OpenWrt 21.02.0 r16279-5cc0535800 / LuCI openwrt-21.02 branch git-21.231.26241-422c175

radio0
Type: Qualcomm Atheros QCA9880 802.11nac
Channel: 36 (5.180 GHz)
Bitrate: 420 Mbit/s
Mode: Master
Encryption: WPA2 PSK (CCMP)
Operating Frequency Mode: AC
Channel: 36 (5180 Mhz)
Width: 80Mhz

radio1
Type: Qualcomm Atheros QCA9560 802.11bgn
Channel: 11 (2.462 GHz)
Bitrate: 65 Mbit/s
Mode: Master
Encryption: WPA2 PSK (CCMP)
Operating Frequency Mode: N
Channel: 11 (2462 Mhz)
Width: 20 MHz

[pluffmud]

I have the same issue (had to roll back)

21.02 / TPLINK Archer C7 V4 / 5ghz signal strength

Has anyone noticed a drop in 5GHZ signal strength on 21.02 vs 19.07.8 (TPLINK Archer C7 V4) ? Performance near the router was normal but very poor at the out lying edges of my house . I had to revert back to 19.07.8 . I have no details so when I go back to 21.02 what info should I be gathering/looking at in order to figure out my issue ?

I am going to install 20.02.1 and gather more info

[pluffmud]

FYI for what its worth

https://bugs.openwrt.org/index.php?do=details&task_id=4124&order=dateopened&sort=desc

[craz]

Have you set your country code?

[pluffmud]

Thanks that seems to have to fixed my issue .
Never had to do this before but thats OK

[stack]

I finally got a chance to test a few things. I verified I do have the country code set. I tinkered with other power settings and tweaked a few things. I still don't have the range I used to, but it works solid and reliably now in the house which is good enough for me for now. Thanks for all the suggestions everyone.