try change 5G channel and security type on your router. update driver too

You bulbs seems reset to factory default after the power outage, otherwise you won't see any wifi signal coming from the bulbs. So the bulbs won't associate with the access point automatically,...

Hi Compton, what's the kasa version on your phone? You can try a different phone to see whether you will have the same issue. Beside, can you share a screenshot of the guest status?

You can try to uninstall the driver and reinstall it as well. You may try the Driver from Realtek for RTL8192EE....

You may have a try to change the channel, channel width on the router, as well as the security type. For example, change the channel to 1, channel width to 20MHz or 40MHz, and the security type to...

Your smart plug is with an old version. You can update the firmware of it. New firmware set a limitation to all of the phones.