this is the real answer. unless you gave the app a bunch of permissions it shouldn’t have, they cannot see what you do/say in matrix. but they don’t need to. you willingly feed them enough information through location/posts/comments/private messages/friends/contacts/+a very long list of things for them you figure out your interests and serve you tailored ads.

if it’s fingerprinting you care about, i’d give mullvad browser a try. it’s a firefox fork tailored to increase privacy and blend you into the crowd (as long as you don’t change any setting/install addons). it’s very very neat.

it says so in the blog post