MW does not of itself imply infinite copies of you, but merely very many copies. To get actual infinities requires additional assumptions which you have not supported or even mentioned.

The version of "many worlds" that Roko is talking about is not that of QM. Rather, it is the one where "all structures that exist mathematically also exist physically". According to the conventional understanding of "mathematical existence", there exist infinitely many mathematical structures that contain a copy of me.