But we don't have anything like FF as an alternative to go from Android. Especially considering banks require "certified OS".
Now the phone is running stock firmware from 2020, with Android security patches from 2020, and with numerous publicly known vulnerabilities. The banks work fine, Google Pay works fine, every Play Integrity check passes, even the strongest one (device integrity).
The only reason I see for it being implemented this way is not to lock the bad guys out from your phone, but to prevent you from doing anything to the banking applications, even through it is still possible through said vulnerabilities.
One of said banks also refuses to run if it detects remote assistance clients on your phone (like TeamViewer), or even Discord, because apparently these were used in scams over the past few years, and we need to protect even the stupidest at the expense of everyone else. How did we come to this "future"? The worst days of desktop Windows weren't even remotely close to this nonsense.
It's also Deep Web, not Open Web.
Furthermore, it's US-based, with an unknown amount of Tencent backing, going back to before even its creation.