IoT Devices failing to connect

Hi all, I have an FWG that I had running with Google Wi-Fi points for my IoT devices and a TP-Link Deco mesh setup for my computer network. I added in a layer 3 switch and then swapped out the Google Wi-Fi points with another set of Deco devices and kept the same SSID, setting up a more segregated network for the IoT devices. I’ve been running into issues getting all my IoT devices back online - first I realized that I had 5GHz off and needed that back online, which solved a bunch of issues, but there are still devices that won’t connect or won’t stay connected. My partner thought it was tha the DHCP Pool was too small, so I expanded the pool. This didn’t seem to help. I’m a bit stuck now; I wanted to clear the DHCP leases manually but I’m not sure how or if that will help. Any suggestions?