Canon is stuck with 2 mounts, the EF-M and the RF, with the RF being the more future proof one. But there is no way to adapt the EF-M to the RF. And there is no way to adapt any other MILC mount to RF.
Meanwhile, the Nikon Z-mount is as close as you can get to a universal mount. You can adapt almost everything E-mount, everything Laica, everything DSLR. And there are videos on YouTube doing just this. Its a combination of the largest diameter with the shortest flange distance.
I forsee Canon getting stuck in indecision.