Throwing this out, would it be possible to charge based on an exponential curve for bytes used? Encourage miners to charge on a exponential curve, making very large things like inscriptions prohibitively expensive while keeping small transactions cheap.
Discussion
Miners don't charge, fees are added to transactions from the sender. Sender attached a big fee; transaction goes through faster. Think of the Mempool as a big queue where people are bidding (attaching transaction fees) to get to the front.