I used to wear pretty expensive Orthopedic shoes which happened to be sued.
As mentioned, there are protective sprays which DON’T ruin the nap the way waxy substances. The product is similar to Scotchguard which allows whatever it’s used on to maintain it’s character.
An absolute essential is a small wire brush. This is what restores the nap. Use it often.
With those two products, you should be fine. But as mentioned, watch out for areas which have been salted as this leaves an ugly white line as it dries. The scotchguard can’t prevent it as the salt sits on top of the surface.
The best thing to do if they do get splashed or drizzles on is to promptly use terry cloth to dry them to absorb as much of the moisture as possible. This also spreads out whatever little dampness is left dispersing it evenly.
Water spots are caused by allowing them to dry on the shoes. By rubbing vigorously with the terrycloth, any remaining moisture dries evenly rather than in isolated spots. And,of course, a vigorous brushing with the wire brush afterward.