So if you work at the same job, wear a uniform and follow the same guidlines, that makes you the same person as your coworker?
Sure on a surface level they are similar, but they're hardly the same character
First you say the only similarity is the T-visor.... then , when confronted with the uncomfortable truth, you fall back to 'well they are different people all together'.
First, Boba is a clone of Jango without the chip, so they are both the same.
Mando is a different person, yes, but so similar to the Fetts that people were convinced that Mando would be revealed as Boba in Season 1.
And if every movie hero dressed like Indiana Jones -- but were different people -- would that be varied enough for you? Of course not. That would be silly. At least, repetitive.
But Star Wars has slogged along on repetition for so long -- since the 2nd Death Star. People like repetition. They like the same regurgitation over and over again. I don't know why. Its familiar, safe, you know what to expect, you get to have the same shivers over again. We all like a good tug again and again... but I like a little variety too.