Simplified scenario (playground):

from typing import TypeVar, reveal_type

class A: ...
class B(A): ...
class C(A): ...

T = TypeVar('T', bound=A)

def fun(*args: T) -> tuple[T, ...]: return args

# one parameter
reveal_type(fun(A()))  # Revealed type is "builtins.tuple[gargs.A, ...]"
reveal_type(fun(B()))  # Revealed type is "builtins.tuple[gargs.B, ...]"
reveal_type(fun(C()))  # Revealed type is "builtins.tuple[gargs.C, ...]"

# multiple parameters, same type
reveal_type(fun(A(), A()))  # Revealed type is "builtins.tuple[gargs.A, ...]"
reveal_type(fun(B(), B()))  # Revealed type is "builtins.tuple[gargs.B, ...]"
reveal_type(fun(C(), C()))  # Revealed type is "builtins.tuple[gargs.C, ...]"

# multiple parameters, different types
reveal_type(fun(A(), B()))  # Revealed type is "builtins.tuple[gargs.A, ...]"
reveal_type(fun(B(), C()))  # Revealed type is "builtins.tuple[gargs.A, ...]"
reveal_type(fun(C(), A()))  # Revealed type is "builtins.tuple[gargs.A, ...]"

is there a way to annotate fun to teach mypy that fun should return tuple[A, B], tuple[B, C] and tuple[C, A] in the three latter cases?