IMO: You're making a multi-generational leap from the 7D to any of the mirrorless cameras. For its time, it was an exceptional camera. Regarding the R5II and the R3, I have many years of use of the R3. My primary use is Ballroom dance photography. Ju...
I have not tried the specific configuration of the BBF button you have defined here. But, I found in most if not all cases I can lock the Exposure with the * button on the back.
