Just to Make Sure - Network

Just to make sure I got the proper understanding,

I have noticed that some of my lightbulbs (Kasa Kl100 and Wiz in particular) have been unavailable since pairing it in a refreshed HA. Reading support forums I believe it’s because my new SSID isn’t split between 2.4 and 5.0 GHz bands ands and rather acts as one and adjusts accordingly.

Solution: Split the bands and rename the 2.4 GHz band accordingly. Same password and such and then repair the unavailable lightbulbs. Is there anything else I should take into consideration or steps I need to do before or after?

Mine works fine with a single combined SSID for years now. One SSID across multiple APs as well.

Maybe try to disable band steering on your router if its enabled.

Even with a power reset and repairing it make connect for a minute or two but quickly becomes unavailable or is slow to respond (which I believe is due to the same SSID and not pinging fast enough). Prior to a reset though, they worked like a charm.