My shutter isn't firing as fast as it should be. Anyone experienced this?

So I literally just bought an R5 two days ago. When I have the mechanical shutter activated and I put the camera in the highest speed drive mode and do bursts, it SHOULD be doing 12 shots per second... but it only takes 7 images per second!

Then, when I put it in electronic shutter mode and the highest drive speed, it only takes 10.6 images per second.

What the hell? This is half the speed it should be when it's in the "High Speed Continuous +" drive mode.

I thought maybe it was because I was shooting on an SD card thing (even though it's one of the fastest v90 cards on the market), so I took it out of the camera and tried again. Same thing.

I pulled up Youtube videos of people firing their R5 at the highest speed, and everyone's sounds noticeably faster than mind.

Anyone experienced this? Is there a way to fix it? Or do I have to drive two hours back to the camera store where I bought this and return it?

Edit: Just found the answer in the following thread - Canon R5 Can not get more then 7FPS in H+ mode Mechanical shutter

I guess it comes down to lens used, battery conditions, etc.

Weird.