The traditional description of the Buddha's physical characteristics include "well retracted male organ" -- so perhaps "androgynous" in that sense.
I understand "alpha" as being a social adjective -- there are alpha males and alpha females -- and the Buddha was "alpha" in that sense i.e. socially: a leader, able to dominate (confidently and indisputably lead or teach) any assembly (of people) and any individual, with kings too (and gods) being respectful.
I think it's rude and missing the point to be asking about people's genitals, but since you ask.
You mentioned in a comment,
please be aware that 'alpha male' derives from animal behaviour, and the need for access to women's bodies / physical intimidation over other males. so you side with the 'macho' buddha
I don't think that's how the term "alpha" is applied to human beings -- some alpha humans might be faithfully married or celibate -- IMO it's just a matter of being recognised as socially superior or second to none.
For example here's a quote from a sutta, MN 12:
Sariputta, the Tathagata has these ten Tathagata's powers, possessing which he claims the herd-leader's place, roars his lion's roar in the assemblies, and sets rolling the Wheel of Brahma. What are the ten?
To answer some of the details in your question, I think it's that the Dhamma (the Buddha's doctrine) is seen as being "best" -- that's why and on the subject of which the Buddha dominates an assembly -- the Buddha is described as "an unsurpassed teacher of Gods and men" but the Buddha himself reveres the Dhamma, see Reference request for "the Buddha takes the Dhamma as his superior"
You might see the Buddha as "submissive", e.g. not flaring up when insulted -- see SN 7.2 -- I wouldn't call that submissive though, I see it as self-controlled, heedful (keeping your eye on the prize), and skilfully cooperative:
You live for the good of both
— your own, the other's —
when, knowing the other's provoked,
you mindfully grow calm.
There's a fair bit of doctrine about not arguing with each other, and about how arguments (including arguments about the Dhamma) might be associated with conceit.