Need an iPad device that ONLY uses 2.4ghz network

I have a situation that I hope this Community can help with. I have an Orbi TriBand Mesh router, that uses 2.4 and 5 ghz networks. And I have an iPhone. This makes it quite a challenge to set up a 2.4 ghz smart device (lights, bulbs, plugs, etc), since, when using my iPhone (or iPad) to set up the new device, it picks the stronger 5 ghz network, and the new device won’t connect to that network. To most easily solve this issue, I would like to purchase one of the older iPads that was only capable of connecting to 2.4 ghz. Then, I could just use that older iPad to do any new 2.4 ghz setups. Could someone that knows about the older iPad models please advise which of the older iPad models was only 2.4 ghz friendly (and won’t even be capable of connecting to the 5 ghz network)?