Infinite doesn't mean everything. Infinite can include a repeating pattern, even a huge repeating pattern which seems random at first. Not everything you could possibly imagine would necessarily have to exist in the multiverse.
And even if infinite and perfectly random, some things may just not be feasible and just not exist.
In an infinite list of letters, every single book ever written, every word ever spoken (and to be written/spoken) should be present no?
I guess the only caveat is that in an infinite universe certain physical laws could be universal (which would prevent eg any universe to break the speed of light)? But some version of me having hair past my 30s should certainly exist no?
This infinite list of letters could be "any random combination of letters EXCEPT when that makes the word "banana". A subset of an infinite set can still be infinite.
I mean, the whole premise is getting this completely wrong. The actual physics idea behind multiple universes is that every possibility in specific quantum events happens, each one being in a separate, 'parallel', universe where everything else in the universe is exactly the same. All the laws of physics stay the same, just the results of all the cumulative random possibilities are different.
This is also not the only explanation of that strange phenomenon in quantum mechanics.