Or consider this.

Anyone who wants to send zaps creates a new user id and gives it a wallet connect. They run a little background app on their desktop machin, or a personal raspberry pi, or a friends computer, or a tiny imgage on amazon. This little app listens on specific relays and waits for incoming DMs from the user that instruct it to send a zap. No custodial risk. The little app should be open source and reviewed by nostrites who can affirm that it does not leak anything.

Now phone apps users can simply send messages (DM or plain text) "Hey @mini-me-xxx, zap #[1] 1,000,000 sats"

I'm sure someone has thought of this before.