The short answer is yes, muzzle brakes can affect accuracy. However, the effect can be very small and the shooter will not notice a difference.
Muzzle brakes work by redirecting the gases that escape from the muzzle when a shot is fired. This redirection of gases can cause the muzzle to rise or move side to side slightly, which can impact where the bullet hits. Data from competitive shooters have shown that this effect can be as little as 0.2 inches at 100 yards. For most shooters, this difference will not be noticeable and will not impact their shooting accuracy.
There are some competitive shooters who do worry about the slight muzzle movement caused by brake use and will choose not to use them for this reason.
However, for the majority of shooters, the benefits of reduced recoil and muzzle rise will outweigh any negative impact on accuracy.
See the video about how the muzzle device affects your point of impact to consider this along with what you just read:
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