I can't prove it but I've always been of the belief that those 3.5-4.5 type bucks who just pop in out of nowhere aren't actually new. I think they are the 1.5yr olds who get chased away.
While I suspect this is sometimes the case, it often isn't.
Unfortunately, most young bucks cannot be identified should they ever re-visit as older bucks.
Back in 2016, I had what appeared to be an albino male fawn born on my hunting land. Later we realized he was only @ 95% white, and did not have pink eyes, so he was basically a white deer. He could be seen regularly until mid-October 2017, usually within a few hundred yards of his birth.
One day in mid-October 2017, I was driving down a nearby county road, and just happened to see him farther from his birth area than ever before. He appears to have just crossed the road, and was walking across a large field (getting farther away). I saw him cross the field, putting him another 300 yds or so farther, then he disappeared. He was 1 1/2 yrs old at the time with a very common looking 4-point "yearling" set of antlers.
I never saw him again.
Every year I've hoped his rut range might bring him back to visit his birth area. If he's still alive, he's now 6 1/2 yrs old. Interestingly, I and friends have been running trail cams in the surrounding area going as far as @ 7 miles in the direction he was last seen traveling. None of us have seen or gotten a picture of him since October 2017 when he presumably dispersed. He may have soon thereafter simply died, but if a hunter had killed him, fair chance once of us would have heard about someone killing a white buck.
A couple years later, I identified another male fawn that appeared to be wearing white knee socks. His legs were completely white from the knees down. Same kind of thing happened. Saw him for a few months, then he was never seen again.
I do suspect some young dispersed bucks to come back to visit their birth areas. Just don't think it happens very much in most areas. Maybe in some urban areas where natural dispersal is more challenging or impossible, perhaps those localized urban deer herds are somewhat like non-migratory geese, all hanging around wherever they were born for their entire lives?