I dunno. I'd be starting all over again and looking for different options depending on the application. One of the nice things about Ubiquiti was that they did several things well.

For plug-and-play home wifi, Eero might be a good choice, with some reservations.

For slightly larger scale prosumer stuff, I might look for a way to use Ubiquiti's hardware but with something like https://hostifi.com/ , maybe with older-generation hardware that I still trusted.

For the DIY hobbyist, pfsense, openwrt, and kin are still popular.

Honestly, mesh networks have been a tarpit forever. It's been exceedingly difficult to make them reliable, with all the features people want (like access point roaming), without spending a lot of time or money. I got out of that niche a few years back and have no desire to get back in to it.