I have FT working to some degree while testing exclusively with iOS devices on 23.05. I have WPA3 enabled as well.
I believe the only other non-default setting I used was
reassociation_deadline=20000
I have a shared ESSID between both bands and two access points. When it doesn't work, I see errors such as:
daemon.err hostapd: nl80211: kernel reports: key addition failed
daemon.notice hostapd: FT: Missing required pairwise in pull response from xx:xx:xx:xx:xx:xx
When it does work, I've switched APs as expected. I believe that I've also hopped/steered (edit: via usteer) from the 2.4Ghz band to 5Ghz without a full handshake. But going from 5Ghz to 2.4GHz, I get a full handshake.