The 2018 and 2020 iPad Pro models share the same FaceID technology. This is a local authentication technology that is essentially tied to the Secure Enclave within the individual device, in which cryptographic keys that secure your data are securely stored.
Banking and other Apps requiring user-authentication rely upon the back-end authentication systems used by the Bank (or other entity). If not using a Web Browser to access their services, their respective Apps provide a mechanism to access the back-end authentication system. Other that the App being written to support specific device requirements, it makes no difference whether you are using an iPad or iPhone - unless the App accesses device-specific hardware. Similarly, unless the bank forbids access over a specific network type, it WiFi or Cellular is immaterial; all network communication ultimately uses industry standard IP network data.
I hope this helpfully answers your question.