Solana fees should be very low. Often it's 0.000005 Sol for a transaction. This app just has higher costs, due to the coding of their smart contracts I think.

It's something I may look into: understanding smart contract costs for different actions. It's a bit nerdy but I want to start coding smart contracts anyway so I'll make it part of that.

Cosmos I definitely need to start playing with more. I've had my ATOM for a while. It's just finding the time!