I had about the same issues. Don’t know your situation, so I can only explain what I did. Homey did not hVe any problems with my new wifi set, but some iot devices did.
Is it a mesh set? My Asus XT8 set performs very well and is superfast, but not with all iot devices. Mesh firmware does not always work very well with some (older/buggier?) iot devices. At least for Asus’ aiMesh firmware.
Always update your wifi set to the latest firmware and check beta firmware too. The latest beta firmware from Asus contains enhancements for iot devices. It might be the same for your wifi set. Google for tweaks which might help in iot connections.
In the end, I activated the 2.4GHz wifi band of my ISP’s Fritzbox routermodem, and connected just the iot devices that gave problems (in my case mostly Shelly devices). Since then no problems at all anymore.
