Phoenix does not support LN addresses so it is not possible to use it for zaps afaik. I'm not sure if it would be suitable for zaps anyway because the Phoenix app runs as a node on your phone, and is only online when you open it and for as long as it runs in the background. If it's not running then...

personally I'm using primal, so sent sats from Phoenix to the primal lightning ID of my user here... but it is the first time I use the LN so maybe there are better solutions ⚡

What did you end up using?