Devices looking for wireless network restricted to 2.4GHz

[johnbday]

Have been considering candidates for a smart line-voltage thermostat (electric baseboard  heater), preferably without the need for a hub. The highest rated appears to be a Mysa <link not permitted>

Their tech support lists Orbi as a problematic router:

"Any router included on our problematic list means it has issue providing a singular 2.4 GHz network. Netgear Orbi has been consistently problematic for many customers as it is a merged/mesh network. Mysa cannot maintain a stable connection with a merged network of 2.4 and 5, it can also not maintain a stable connection if the 2.4 and 5 networks share the same network name and SSID."

Tech support for BigAssFans (Haiku) and Ecobee (smart thermostats) don't go quite as far but also report the Orbi as problematic for the same reason. All told I have about 30 of those devices (some of which have wall contols so there are two WiFi connected devices for each fan, for example)

Anyone have a workaround or experience with these devices?  Is it possible (or wise) to have either Orbi wireless network limited to 2.4?

Thanks in advance and Happy New Year

[plemans]

many of them are going to say that because customers don't know how to set them up, and they don't want to deal with having to help people get them setup. 

I'm running an ecobee right now on an orbi setup. Works fine. Setup went fine. 

There's a few work arounds to get them running sometimes but it usually isn't to much of an issue. 

I can't attest to your "smart line-voltage thermostat" . 

Worst case scenario is buying a super cheap 2.4ghz router and run it in AP mode for devices that have issues.  You could either just run it all the time or you can use it for the setup process. I've actually done that when Orbi first came out and was having major issues with this. I had the cheap router setup with same ssid and password. I'd get the device all setup, turn off el-cheapo router, and then turn my orbi back on and it'd link to the orbi. i haven't needed to do that in a long time but it worked when the Orbi was still pretty beta. 

[SW_]

@plemanssuggestion is simplest.  I had also done that in early Orbi days with 2.4GHz only SSID via an old Asus router.

Fortunately, there's workaround via Orbi Guest network.  Basically, you can setup separate 2.4GHz and 5GHz SSIDs via Guest network.  If you're comfortable with telnet cmd, check out this post: How to separate SSIDs on Guest Network.