If you’re a client just add payment targets functionality, even if you want to make an onlyism client then make a fork of payment targets that shows only your currency from the payment targets lists on there. The ideal is some sort of BIP 39/BIP 44 multicoin wallet being generated from a NSEC Key derivation in clients like the spark wallet thing a lot of clients have done recently. Even if you want to make an onlyism client, having the default payment route through that currency is easier than each client/coin having a separate standard that needs to be reimplemented to be compatible. Then make everything else into a copyable bio snippet or something.