99% of what he did is not needed. Only 2 things are needed: enable fast roaming (FT), and change DTIM from the openwrt default of 2, to 3. That's all. No need to install usteer, extra hostapd fields. Nothing.
By lucky chance, while he set up usteer, he modified DTIM to 3 thus fixing the fast transition roaming, which doesn't work well on default openwrt because of DTIM. Especially Apple devices really hate DTIM=2 (they need the extra off-time given by DTIM to properly scan the other channels).
Actually, no. DTIM was always 3, if you'd bothered to read the original post - https://taoofmac.com/space/reviews/2025/09/14/1630
I do know what Apple devices "like" (it's kind of my thing, hence the domain name).