you can run a lightning node from your phone. this approach is usually sub-optimal for receiving payments and a no-go for routing. it does function decently for sending payments. ideally you'd back it with a full node rather than trusting the default full node.

if you're interested in exploring this avenue, check out these two projects:

Blixt Wallet - https://blixtwallet.github.io

Open Bitcoin Wallet - https://github.com/nbd-wtf/obw

a more optimal approach would be running your own always-online full node and use a mobile app like Zeus (https://zeusln.app/). you could easily purchase, or build, a full node by selecting a package such as Start9's Embassy (https://start9.com/).

check my profile if you need DIY hardware.