I would think legacy 2.4 devices should still be able to connect. What trouble are you having? Do you only have one SSID being broadcast and can you connect to it with your doorbell and opener?
Well my two devices are both finicky anyway when it comes to connecting to WiFi... what I don’t know is if it has anything to do with my route’s combined 2.4 GHz & 5 GHz or whether it’s due to its flakey software. The way I understood the installer is that the two bands were combined instead of being able to select one or the other like you normally can... then whichever band was stronger that was selected.
Just got off the phone with garage door opener tech and I was able to connect by taking the controller next to my router and it did connect to WiFi. Then I took it back to the garage and hooked it back up so it’s working again.
Now he did see how his device or other devices that could only run on 2.4 GHz might have issues connecting when the router combined the bands. In fact he said I can’t guarantee my garage door opener will connect without you calling your ISP and having them separate the bands... luckily it did.
It’s still possible the combined bands are keeping my doorbell camera from connecting suppose I’ll have to try connecting their tech support again.