Cannot import local type stub (.pyi)

[smiRaphi]

Describe the bug
I'm trying to import a local typing stub (lib.cryptox="lib/cryptox.pyi")
But it's telling me "Import lib.cryptox could not be resolved from source" (I also tried just ".cryptox" but same thing)
When I added the whole lib directory as "include" in pyrightconfig.json, I was able to import it via from cryptox import MT19937

Code or Screenshots
lib/cryptox.pyi:

from typing import Self

class MT19937:
    STATE_LENGTH:int # readonly
    STATE_M:int # readonly
    MATRIX_A:int # readonly
    TEMPERING_MASK_B:int
    TEMPERING_MASK_C:int

    def __init__(self,seed:int=None) -> None: ...
    def init(self,seed:int) -> Self: ...
    def s_rand(self,seed:int) -> None: ...
    def rand(self) -> int: ...

lib/crypto.py:

from lib.cryptox import MT19937

VS Code extension or command-line
VS Code extension