Band steering? Not really.
Ross AllanThis post is deleted!
Do you use the same SSID as your old router?
My Apple watch wouldn't connect at all. Wat I did on my apple devices was forget the wifi network. Make a iCloud backup. Reboot the apple device. Make connection to your network again. Working for months after it without problems.
It worth a try if you using the same SSID as your old wifi network.