Does current 64-bit Unity still support 32-bit (x86) native DLLs?

I have a large x86 DLL with a nice C API, and an Interop file in C# that works perfectly, except in Unity. I've set all the options I can find to x86, and I've tried putting it in Plugins/x86.

Either it just doesn't find the DLL, or it finds it and complains that I need to convert it to 64-bit. But I can't do that.

Either (a) somewhere is a key factor I'm missing or (b) it can't be done and my project is dead. Which is it? A bit of sample code or a tutorial would help. I'm out of ideas.

The key to my question is that this is only about Unity, not about the general issue of x64 vs x86. The other questions are irrelevant.

And the answer is: No, you cannot use a 32-bit DLL in the Unity Editor but Yes, you can use 32-bit DLLs in a build of Unity with an x86 target. Unity allows you to provide multiple DLLs to target different platforms, but for the Editor it has to be 64-bit.

I think that's a reasonable question and a useful answer, which I have not seen stated elsewhere. I don't think it should be closed.