KN94 has similar effectiveness to N95 masks, which is probably good enough in most cases. There are masks with better protection like P100 respirators, but these are probably overkill and inconvenient for most uses. The biggest factor that most people, even healthcare workers, overlook is the fit of the mask because it doesn't matter how much the mask protects you if you have gaps where ambient air can flow in. I've heard KN94 masks can be slightly finicky in this regard, so switching to N95 might help but it just depends on your face shape. Also, no facial hair as that effectively nullifies (cuts efficiency in half) the protective properties of masks if it intersects with where the mask meets your face (a mustache might be okay, but no full beard).