You got options

Open WebUI https://github.com/open-webui/open-webui

Run this on a machine, perhaps the same one as ollama. Connect it to ollama. Connect to the web UI from your phone.

Ollama App https://github.com/SMuflhi/ollama-app-for-Android-

Install and connect to ollama.

Maid https://github.com/Mobile-Artificial-Intelligence/maid

Same as above.

Use tailscale to connect to ollama remotely.