I cut my own hair and have always cut my sons’ hair. My last regular barber became somewhat of a “celebrity barber” which made booking him almost impossible, so I just put in the work to learn how to do it myself.

To your question, I think there are multiple answers. But most are going to stem from the fact that to have a fresh cut look, the actor will have had to have gotten a fresh cut. That day. Seems simple but there are reasons both in and out of universe why that is difficult or just wouldn’t work.

When shooting a film they need to have continuity in the shots - so if a lineup looks slightly different on Monday vs. Tuesday, or in June vs. September when doing reshoots, that could be a problem.

On top of that, in universe it doesn’t make sense in many cases for a character to have a “straight out the barbershop” look. You mentioned Kang…when we first saw him as He Who Remains he was isolated in another reality at the end of the time. It would be weird for him to have a super crispy lineup like he left the barbershop within the last couple hours.

You could argue that instead of the SUPER crispy lineup look they could have a clean cut couple day old haircut. But back to continuity- that is difficult to keep consistently looking exactly the same. So to that point o think it’s a decision to go with a looser haircut style. Denzel, Jonathan Majors, and many other Black Hollywood actors usually go for that type of look in real life anyways. You could bring up Obama as an example of that look also.