I agree that 'free' is a trap and bots are a problem. So maybe there's a way to add cost without forcing people to part with money if they don't agree.

Maybe a client side filter that allows you to hide responses that are not accompanied by a zap from the same user.

Pair that with the ability to voluntarily configure a minimum zap amount for reaction emojis.

People can then choose to have broader engagement to their responses, or not. Consumption of content is not penalized. Action is voluntary, and bots now have a real world cost to even be visible.