The decision is always client side, just like with roaming.

There are ways to influence the client, which is basically what Ubiquiti is doing (and the client can ignore), and the last resort is to always kick the client once the signal is below some threshold.

In addition to band steering (which is moving between bands on the same AP), there is also Wi-Fi EasyMesh[1] which allows multiple APs to coordinate with each other (over wired or wireless backhaul) to steer STAs (clients) between APs. However, the Ubiquiti AP is not certified for EasyMesh[2].

[1] https://www.wi-fi.org/discover-wi-fi/wi-fi-easymesh

[2] https://www.wi-fi.org/content/search-page?keys=ubiquiti

I had a minimum rssi set for an ubiquiti access points 5ghz channel. The client would just keep reconnecting to the 5ghz channel and getting kicked immediately. I had to manually lock that device to a specific band and access point. Insanely bad software on the client and very frustrating.

It is often the _device_ that needs better band steering abilities and the Access Point can't do much to force the issue.

Or did you mean that the GP should upgrade both their WAP AND all of the their connecting equipment?

I use that feature on my Dream Machine. It doesn't really help. My laptop will still hop on the wrong band or AP, or my phone will drop off if I'm in the back yard. Meh