I doubt its based on colour really. Our friend who is white, and in his mid 50's can cum 3 sometimes 4 times over a 3/4 hour play session with my wife. Admittidly he doesn't cum at all in the week leading up to us meeting up with him, but his first ejaculation is always very strong and he cums quite a lot obviously, the rest are just normal to even very little cum, but his orgasms are just as strong. He has no issue at all getting hard again within 20 minutes (with a little help from myself or my wife
In saying that, he is extremely fit (semi pro ironman) doesn't ******* that much alcohol, doesn't smoke, drinks plenty of water during the day and train 2-4 hours a day everyday.
But as a cuck who masturbates probably way too much, at 53yo I can still cum 3/4 times in a day if I have the house to myself, and could 6-8 times a day in my youth. If your horny enough, your balls will ache regardless of colour or alpha/ beta status. I'm sure there are plenty of other cucks here who can wank and cum constantly with only a small break in between.