Follow-up from "Apply new msgspec based schemas"

The following discussions from !244 (merged) should be addressed:

• @kudmich started a discussion:

  ?

• @kudmich started a discussion: (+1 comment)

  don't understand this changes, how i can create a PublicKey & PrivateKey object? why i cant provide an AccountName and secret?

• @jziebinski started a discussion:

  Shouldn't TestT be used for annotation purposes only? Also, the conversion to AssetNaiAmount is not necessary?