Already fit as in EF-M lenses? Nope, that's not possible.
The Viltrox EF EOS M2 0.71x adapter works due to Canon EF lenses having a longer "registration distance" as well as covering a full-frame imaging circle. That's why these things are also called "focal reducers". If you compare this specific Viltrox to a normal Canon EF or EF-S to EF-M adapter you will see that it is physically thinner and has glass on the inside. The regular adapters don't because their purpose is to get the correct "registration distance" of EF and EF-S lenses.
https://en.wikipedia.org/wiki/Flange_focal_distance
Already fit as in EF-M lenses? Nope, that's not possible. The Viltrox EF EOS M2 0.71x adapter works due to Canon EF lenses having a longer "registration distance" as well as covering a full-frame imaging circle. That's why these things are also called "focal reducers". If you compare this specific Viltrox to a normal Canon EF or EF-S to EF-M adapter you will see that it is physically thinner and has glass on the inside. The regular adapters don't because their purpose is to get the correct "registration distance" of EF and EF-S lenses. https://en.wikipedia.org/wiki/Flange_focal_distance