I run multiple SSIDs in different Networks and those are 2 of them on the 2.4 GHz Band. Once with WPA2-PSK and once with WPA3-SAE/WPA2-PSK mixed mode. The one with only WPA2-PSK is the one all my Smart Devices connect to. And it works. I run this config on 1x 1900ACS and 2x 1900AC.
I also have a WRT1900AC running OpenWrt v21.02, and it works well with all of my devices.
It did take quite a bit of time reading forum posts and some trial and error to setup to make everything work properly.
Here are some additional config. settings that helped my setup (which you might try if you haven't already):
To help prevent network drop-outs
uninstall default wpad-basic-wolfssl opkg, and
install wpad-openssl opkg: (don't overwrite existing files)
Remove SSID entries (not radios) in Wireless page
Add new entries from radio listings + configure.
Also, add opkg irqbalance.
Change 'enabled' from '0' to '1' in '/etc/config/irqbalance' for improved Wi-Fi performance.
Patch the firmware for 88w8864 (mwlwifi specific high latencies) by disabling tx_amsdu:
Add in luci > startup > local startup the following commands:
Your tips are helpful and I have followed all your tips.
My smartphones now have a stable wifi connection.
But the robot vacuum cleaner still does not connect.
However, I have found a solution/workaround for the vacuum cleaner robot.
Just enable the option option legacy_rates '1' for the 2.4 GHz.
Now the vacuum cleaner robot connects to the OpenWrt 21.02.1 2.4GHz Wifi.
That reminds me that I'll have to test for that issue, too, when I get the chance to upgrade. The default for that setting is "unchecked" in relatively recent OpenWRT builds. Annoyingly, in the past, if it was checked, it broke Roku connectivity! Corroborating instances of this can be found in the Roku forums. I don't know if this still holds true in 21.02.
Thanks for the info. about possible Roku connectivity issues as well. I hope this issue is resolved in 21.02.1, but if not, perhaps this issue could be fixed with a mwlwifi driver update which would allow us to be able to use all our modern devices without compromising the transfer speeds?
A driver update is very unlikely to happen, which is discussed in the following, but, just to be sure, have you been following the WRT3200ACM & WRT32X thread where they've fixed a major issue on it in the 21.02 daily snapshots and the master for this family of devices? That was what I was talking about me needing to test. You should definitely test a 21.02 daily snapshot and/or the master to see if it solves your problems. The 21.02 daily snapshots are in a hidden directory, but someone can probably send you a link to it.
However, my Motorola Moto G30 really is struggling to get past 150Mbps on the 5GHz channel despite the link speed being 433Mbps. On the other hand, the Moto G30 will complete an Ookla Speedtest at a lot higher speeds of 220~Mbps on my BT Smarthub 2.
I sometimes think it could be my phone because my older Uelefone Armor 8 phone has a fairly close benchmark score to the Moto G30 and yet that will complete Ookla Speedtests at 250Mbps on OpenWrt.