When you go to attach, there's just a list of options, none of which I understand.
We hear you. We started with protocols like NWC to cover as many wallets at once as possible but we want to switch to showing wallets with logos etc.
I wrote a bit about that in this Github comment if you're interested (or any other reader of this comment).
Even now the NWC option only shows that it's attached for funding on my desktop, and not mobile. I have no idea why.
We're working on syncing the spending credentials across devices end-to-end encrypted. They are currently only stored on the device you setup since they are pretty sensitive (they would allow us to steal from you) unlike the credentials to receive. There's a disclaimer on the wallets about that:
Wallet Security Disclaimer
Your wallet's credentials for spending are stored in the browser and never go to the server. However, you should definitely set a budget in your wallet if you can.
Also, for the time being, you will have to reenter your credentials on other devices.