These types of activities I save for my Ethernet-wired PC at home which has Bluetooth and Wi-Fi disabled. Nothing is perfectly safe in the computer world, but performing sensitive activities over the airwaves is just increasing the risk.
That’s kind of what we do. Would never do anything financial via cellular. And at home we have one of our PCs strictly for financial things and shopping, and never ever do web surfing or email on that system. Supposedly most breaches come in via email.
We do have email on the Android devices because we were told you can’t use the phone without one. But we never use those email addresses.