Also don't you have an onsite technical interview process that you use to assess the candidates abilities which invalidates any need for online coding tests?
If you can't answer yes to these questions. Unfortunately you are part of the problem.
Of course I have to trust the candidates that they made the homework themselves, but if you don't start on a trust basis that would be a really bad starting point. There's still probation to make sure they're a good fit. I'm investing a lot more work into vetting when it's an overseas candidate compared to local, but mostly to make sure we don't put someone on the street, because I didn't do my job properly.
I do have the experience, and have the code to show. Why would I be subject to a "homework"?
This process objectively discriminate against people with enough age and experience, but don't have the time outside work. Even just not having the will to do a "homework" is an enough reason to pass.
Are you hunting for young eager engineers who can put the most to self proving, or a diverse experience base?
I am not suggesting anything against your process, but highlighting the shortcomings.
I would probably pass your interview process directly.