Having seen a few slippery slope situations like this over the years with IoT and other services, I'm simply not willing to make any concessions in that direction. I use a UDM Pro and turning on cloud access requires associating that hardware with a Unify cloud account. That's already undesirable if you want to safeguard privacy.
Fair enough, the Unifi brand is a consumer/prosumer brand after all.
I guess if you have strict privacy requirements then you would be looking more at enterprise gear anyway.