what is mean alpha guy/male?

The term gets thrown around by different groups for different reasons so it depends on who's definition you want to accept.

Basically it just means a male who is self confident, willing to always make decisions and self assured about those decisions. Some other features are leadership qualities or the ability to entertain people with good presence. Their friends admire them for their ability to hold conversations and keep everyone entertained.

Wonder if we call the fella at the other end, 'Zeta'

No, Dale, we call him "Omega".

Geez!

Oops Tim, yea now 'mem
...just wait'll 86

In that case, I'd prefer to abridge my existence..

It can also simply mean "the one in charge" who others follow.

Of course, looked at another way, the idea of the "alpha male" is just bullsh*t straight from the manosphere, much cherished by males who think like apes.

I wonder who the thumb-downer was? (I think I know.)