Some devices cannot connect to 2.4

I recently installed a couple additional WiFi light switches (not sure if this is related) and had to cut power to the part of the house that powers the router. When everything was powered back up all seemed to work fine and connect without issue but now a few of my devices, my iPhone, kindle and only one Echo will not connect to the 2.4 GHz band. it’s not an issue with the phone because that can connect to the 5 GHz but my Kindle and echo can only connect to the 2.4 so now they are essentially useless. I tried restarting, resetting the router and for a minute my phone connected back to the 2.4 and then dropped off again. Says unable to join. Every other device in the house can connect to the 2.4 except for my phone, Kindle and echo. Any ideas or suggestions?