This is an alternate solution to MR 6761 [1] (actually is based on comment in that MR).
WriteProcessMemory() should succeed when process handle doesn't have PROCESS_QUERY_INFORMATION access right set (test attached). Plus some additional cleanup in test for ReadProcessMemory().
Feedback from Proton says that this patch solves the reported game issue.
[1] https://gitlab.winehq.org/wine/wine/-/merge_requests/6761