The signing part is, I believe, just to prove you own the on-chain address and are the one providing the Bolt12 offer for payment. I don't know that Coinos needs to support anything. You still have an address like if you received payment on-chain.

OCEAN

Lightning Payouts

you have to be able to make specific offers with the right description. if coinos just gives you a bolt12 offer to use with your custodial wallet, then it wont suffice.

+1