Canon provides focus respiration correction help to f/2.8 and f/4 RF zoom lenses by way of firmware

No, SA adjustment is a function, focus shift is a matter . And if Canon can appropriate focus respiration, they positive may appropriate by way of firmware focus shift.

The EF model of the 100mm IS macro had focus shift, it simply wasn’t as apparent. I do not consider focus shift may be corrected in firmware. Canon has up to now developed lenses to cut back the impact, the EF 50mm f/1.2L being an instance.

I do not recall ever seeing a firmware replace that corrected focus shift. It is 2022 although, possibly it is within the works.

Most, if not all quick lenses have focus shift to a point.