I found the below extremely effective at curbing addictive behaviors myself.
Find somebody you trust and have them password-protect your Screen Time settings and lock them down. Uninstall anything you don't want distracting you. Disable literally everything except the banking apps, texting and calling.
If you really need to get into your phone for whatever reason, there's a feature that allows you to request time.
You can also always wipe the phone using any computer with MacOS on it (or just take it to an Apple Store) if things become desperate.
DO NOT click the button that prompts you to persist your Screen Time settings to iCloud--that crap is nearly impossible to get rid of, and you'll be stuck creating a new iCloud account if your friend disappears for whatever reason.
If you can't do the above for whatever reason, then I'd suggest changing your banking memberships so that you no longer depend on phone apps. If you're really serious about solving your problems then you'll need to be ready to do "whatever it takes."