I think this is something different. You can set max fees/fee rate that you’re willing to pay when sending a payment. If it can’t find a route within that limit then the payment will fail.
Discussion
Why is it on the receive screen though?
Oh right you are. You can set max fees you’re willing to pay when a new channel needs to be open. 
Can I connect to my nostr.build node to keep fees low?
Not with Phoenix. Breez, Zeus, and Blixt are other node in phone wallets that allow you to connect to other nodes. Phoenix is only to ACINQ’s node.
No, but you can use nostr:npub1xnf02f60r9v0e5kty33a404dm79zr7z2eepyrk5gsq3m7pwvsz2sazlpr5 as an interface to your node
Looks like only ASINQ, but still struggling to open the channel… This is the problem.. There needs to be a simple Lightning wallet that just works….
Muun is a non-custodial wallet that just works and it works really well. The problem is that it’s expensive to use when onchain fees are high. There’s always tradeoffs. Also, there’s many custodial wallets that work well and are good enough to use for things like zapping.