Mac client.

Why isn't it possible to download a Mac client?

Installing virtual machines to install Windows and use the Windows client is an option that works more then decent.
But next to an extra step to play the best game in the world it is also a limitating step for Apple users who can't use the full power of there fast M series (Normal, Pro Max or even Ultra) Processors, Ramm's and SSD's. (By virtualizing them)

Some private servers do, Blizzard does (Classic) but Warmane doesn't (anymore).

I am just curious if people are working on it behind the scenes, to give Mac users there own client.

Because the M processors did not exist when 3.3.5 was released, so a 3.3.5 client for M processors does not exist.

Is it the M processor that is the problem? Or the 64 bitt (I am not a tech dude) OS apple uses?
Is it very hard to learn the 3.3.5. client to "speak" either of those two?
Are other servers using the new (?) Blizzard Mac Client?

Again just curious, using vmware and windows 10 does work (both on Intel and arm) but I want to use all of my cores from C and GPU if it is possible.
Or should I just think back to the time from 3.3.5 when PC's where using only X cores, Memory etc and give that to the virtual machine (or if higher stick to the minimal specs for windows 10).
Again not a tech guy and certainly not a Windows expert (more a Windows baby).

It's a little bit of both things. During the time the 3.3.5 client was the current client, macs had 32-bit Intel processors, and therefore the only binary released was that, a 32-bit Intel binary. Current processors are 64-bit M (ARM) processors. Even though macos has a compatibility layer, Rosetta, that allows you to run Intel executables, it only works with 64-bit Intel executables.

Some vanilla servers allow you to play using the vanilla classic executables (both Mac and Windows), but that's not the case of warmane.

If using vmware there is no reason not to give it access to all processors, but it won't use them all. I'm not sure what the practical limit is.

There is also the option of using wine (or whisky, or crossover) but I don't know if it works. People say it doesn't.

If I recall, it's the M not supporting the 32-bits client anymore, or something around those lines, so all you can do to use it is emulate with a VM.
The "Classic" client is 64-bits and based on a later expansion, not on the original WotLK core, so it also isn't a matter of "just use the new one."