"Trustworthy" requires a qualifier of "for what" and I do trust Google to not intentionally install malware on my device and to take reasonable steps to prevent other people from doing it. I will admit that I don't know the details of how the app stores work, but they are at least checking the hashes of the binaries right? The probability of trying to install Instagram from Meta, but actually installing Instapwned from some malicious third party is zero when you go through the app store, right?