Camera manufacturers never lie However, they may stretch the truth a TAD That is why, I would never purchase a camera until it has been distributed and tested by independent testers...
Case in point! The burst speeds of both the Canon EOS R and the Nikon Z-7.
Tony Northrup might not be the final authority on testing cameras but, his test results might be worthwhile investigating. In a YouTube video on which mirrorless camera is best for sports, he asserts that the EOS R does do the claimed burst speed UNLESS the camera needs to adjust focus while shooting (as when following a moving subject). When focus adjust is needed, the camera bogs down terribly,
Apparently the Z-7 MAY have the same slowdown problem, but not to the same degree as the Canon.
I listened to the YouTube video on my car radio as I was driving, so I don't have a URL for the YouTube video. But, if you are considering either of these cameras and expect to shoot some fast action, it might be worthwhile doing some research...