“they put ads in the terminal” isn’t really accurate.
Their “ubuntu-advantage-tools” adds information to one of their other products to the output of apt. You can easily get rid of that by uninstalling/replacing “ubuntu-advantage-tools”. It’s definitely not like they are selling ad space in your terminal to third parties.
You mean, don’t trust a flatpak uploaded by a random person, but if there are enough fake reviews, it can be trusted?