The R100 features Canon’s newest RF-mount and the M50 II features the older EF-M mount.You can’t use EF-M lenses on the RF mount or vice versa and Canon does not make an adapter.
The R100 has a fixed LCD display and is not touch enabled.The M50 II has a multi-angle LCD monitor that can be flipped to the side and rotated 180˚, it is touch enabled.
The R100 has a normal ISO range of 100–12800 and an expanded range up to 25600.The M50 II has a normal ISO range of 100–25600 and an expanded range up to 51200.