Canon already released its 100mm 1.4x f/2.8 macro in RF mount. Traditionally, it has maintained a couple other macro-dedicated focal lengths: one around 65mm and another around 180mm. It recently patented some designs in the 140mm to 200mm range.
The recently-released 100mm RF lens is a corker, with image quality higher than that of the much-loved EF 100mm f/2.8 L Macro. They also added a puzzling “SA Control” feature that seems to give shooters the option of reducing image quality, and was probably designed on paper originally to better smoothen out bokeh.
A 180mm f/4 lens, the likeliest of these designs to see a manufacturing line, would be welcome among those shooting macro for living creatures, such as easily-spooked insects.