You have to do some digging to get downgrade firmware. This site has a working link to v3.2 https://www.kiwivoip.co.nz/support/unifi-uap-lr-old-firmware-upgrade/

I’ve never actually done the process tbh. All I know is I keep cleaning them up and people keep buying them in packs of 3 🤷

I refuse to install Unifi equipment nowadays. They’ve alienated professional installers over the years in favour of targeting prosumers.

They are. I get dozens of them to refurb and they always get bought on eBay for this.