I've done a little comparison of some different batteries and the R5. Not scientific at all but some stats for battery life etc as I use the camera. The camera seems happy with the K&F Concept batteries and does not give an error about non-genuine batteries (unlike my 5DsR).
Right a bit of background of how the R5 uses a battery and its frame rate. If you set the camera to high speed continuous+ (green H+ icon) it has 3 modes - A, B and C which are dependant on how much charge is in the battery. Mode A (green H+) can achieve up to 12fps, mode B (white H+) can achieve up to 9.2fps and mode C (blinking white H+) can achieve 6.8 fps.
As a battery runs down the frame rate will move to the next lowest mode at certain percentages of battery power that's left. This is where I've tried to find out at what point different batteries change mode.
Now the numbers.

Canon LP-E6N battery (2+ years old) - Mode A works till the battery is at 46% (282 shots), Mode B then continues down to at least 5% (total 431 shots) I then had to change battery. Never reached Mode C.

Canon LP-E6NH (1 month old) - Mode A works till the battery is at 38% (399 shots), Mode B then continues down to at least 5% (total 462 shots) I then had to change the battery. Never reached Mode C.

K&F Concept LP-E6NH (2 weeks old) - Mode A works till the battery is at 75% (150 shots), Mode B then continues down to at least 5% (total 420 shots) I then had to change the battery. Never reached Mode C.

Obviously the genuine Canon NH battery is best but most expensive. The K&F Concept has less overall shots than old Canon N batteries but not by much and this test was all just based on one use of each battery. They may even out a bit more when averaged.

Anyway, if you need 12fps for the longest time then you have to get the genuine Canon NH battery. If 12fps for the first quarter and then 9fps for the rest of the battery is good enough then the K&F Concept batteries are awesome value for money. Personally I don't have a problem with the slightly reduced fps compared to spending £150 on a single Canon battery.
Of course if you go on to electronic shutter then you get 20fps at any battery percentage.
Hope that helps.