Ok... so you're running a snapshot. But the kernel version you have now does not match what you said earlier. Nevertheless... [EDIT: where did this image come from?]
Any particular reason that you are running a snapshot instead of a normal stable release build? Are there specific things about snapshot that you want/need?
I would recommend making a backup and then installing fresh. Do not restore your backup, but rather use it as a reference (if you need it) to recreate your settings.
Take a look at the information here about how to install OpenWrt onto your Pi.
this is a custom build so you should seek help for it here rather than on the general forum
thread title says lan and comment above says wlan... i'll assume its wireless related...
basically psherman s advice is pretty much correct in that if you had something working already on older firmware... there have been reported issues with onboard wifi since the original 21.02.1 build/release...
anyone using onboard wifi should stick to the original 21.02.1 images and not upgrade packages...
fwiw: i've never seen a dual ssid (iot + guest) functional on these devices... so it would be news to me if you'd achieved that...
I'd recommend installing a fresh copy of 21.02.1 as I had suggested earlier. Do not use your previous backup, but you can use that as a reference as you configure 21.02.1.