Around a dozen banking apps have begun specifically permitting GrapheneOS in addition to Google-approved operating systems, and the number is growing. Examples include AmeriCU Credit Union (US) and Switzerland’s UBS & UBS key4, which officially(!) support @GrapheneOS There's a good crowd-sourced list based on ongoing user reports:

Banking Applications Compatibility with GrapheneOS

Maintained Compatibility List for International Banking Apps This list includes banking apps that have been tested, submitted, reviewed, and verifi...

h/t

Stasher News

Banking Applications Compatibility with GrapheneOS \ stasher news

Maintained Compatibility List for International Banking Apps This list includes banking apps that have been tested, submitted, reviewed, and verifi...