Believe me it is unrealistic, the rate, the way it looks, everything… An aircraft parked overnight in freezing fog will look like that, inflight icing wont look like that as it builds up on the frontal surfaces only (apart from some flowback in case of SLD). Also the type of ice (frost) is wrong. It will not built up nearly as fast, especially in light clouds with low moisture content. Not impossible, just extremely unlikely. MSFS currently only has a severe icing mode and it turns on upon entering icing conditions, no matter the moisture content / droplet size / total air temperature / airframe and fuel temperature etc.
To the OP, there are many posts about this already with far more votes. Splitting the votes is not gonna be productive so please close or merge this thread with an existing one…