How to get uncompressed BTC address and private key from bit module for Python?
It looks like doing such a conversion is not well supported, nor is instantiating a private key as uncompressed unless you do so with a WIF key.

However, you can change the compressed-ness by doing:

key._public_key = key._pk.public_key.format(compressed=False)


But this requires you do to this immediately after instantiation as otherwise precomputed properties such as .address will not be recomputed.