i used fdroid when i used Android, but now i feel like it is a false sense of security. like, yeah, the apps themselves might not have telemetry, but the whole OS itself is a giant spyware made by the largest ad company in the world, so unless you are using a rooted, custom rom that has taken all the google apis out of the way, i still feel that my data is safer in ios than android with fdroid. the only real way to have data fully safe is too minimize the use of apps completely thou
i would use apps from an ios version of fdriod, if i had the chance, thou, so i think your point is valid