Looks like the long double issue is still there in 3.11

>>> import gc
>>> gc.set_debug(gc.DEBUG_LEAK)
>>> import ctypes
gc: collectable <function 0x0000026417BBE200>
gc: collectable <tuple 0x0000026417BE0040>
gc: collectable <dict 0x0000026417BC56C0>
gc: collectable <type 0x0000026417AD9840>
gc: collectable <tuple 0x0000026417BD6540>
gc: collectable <getset_descriptor 0x0000026417BD6580>
gc: collectable <getset_descriptor 0x0000026417BD65C0>
gc: collectable <tuple 0x0000026417BE05E0>
gc: collectable <_ctypes.PyCSimpleType 0x0000026417AE4E10>
gc: collectable <tuple 0x0000026417BD96C0>
gc: collectable <getset_descriptor 0x0000026417BE9080>
gc: collectable <getset_descriptor 0x0000026417BE90C0>
gc: collectable <StgDict 0x00000264178A5490>
>>> gc.garbage
[<function _C._m at 0x0000026417BBE200>, (<class 'object'>,), {'__module__': 'types', '_m': <function _C._m at 0x0000026417BBE200>, '__dict__': <attribute '__dict__' of '_C' objects>, '__weakref__': <attribute '__weakref__' of '_C' objects>, '__doc__': None}, <class 'types._C'>, (<class 'types._C'>, <class 'object'>), <attribute '__dict__' of '_C' objects>, <attribute '__weakref__' of '_C' objects>, (<class '_ctypes._SimpleCData'>,), <class 'ctypes.c_longdouble'>, (<class 'ctypes.c_longdouble'>, <class '_ctypes._SimpleCData'>, <class '_ctypes._CData'>, <class 'object'>), <attribute '__dict__' of 'c_longdouble' objects>, <attribute '__weakref__' of 'c_longdouble' objects>, {'__module__': 'ctypes', '_type_': 'g', '__dict__': <attribute '__dict__' of 'c_longdouble' objects>, '__weakref__': <attribute '__weakref__' of 'c_longdouble' objects>, '__doc__': None}]