this is patently false

block A versus block B, one without shitcoin transactions, or less, than the other

usually 90% or more of the rest is identical

you would know that if you had read the code

it happens all the time that there is a reorg, once a year or more, and nobody has successfully made it bend in their favour, and seriously, nobody has even hardly tried to do a 51% attack in forever

the chances of a reorg falling in your favour worse than you flipping heads 10 times in a row

usually the hashes are different enough that the next one that comes settles it, one is lower, other is higher, difficulty stays the same, and the other is like 2 higher, chain says no to fork