CPython since 3.8 already has built-in audit events, including open, so you don't need to patch anything or use anything external. Just add an audit hook with sys.addaudithook().

Quick example:

    import inspect
    import pathlib
    import sys


    def callsite():
        try:
            pathlib.Path("/tmp/file").open()
        except:
            pass


    def audit_hook(event, args):
        if event == "open":
            path, mode, flags = args
            print(f"audit: open({path!r}, {mode!r}, 0o{flags:o})")
            # Not using traceback here because traceback will attempt to read the
            # source file, causing an infinite recursion of audit events.
            f = inspect.currentframe()
            while f := f.f_back:
                print(
                    f'File "{f.f_code.co_filename}", line {f.f_lineno}, in {f.f_code.co_name}'
                )


    def main():
        sys.addaudithook(audit_hook)
        callsite()


    if __name__ == "__main__":
        main()

Prints:

    audit: open('/tmp/file', 'r', 0o100000000)
    File "/path/to/python/lib/python3.12/pathlib.py", line 1013, in open
    File "/tmp/audit.py", line 10, in callsite
    File "/tmp/audit.py", line 26, in main
    File "/tmp/audit.py", line 30, in <module>

https://docs.python.org/3/library/audit_events.html