The smallest Modells that I run on my PC take about 6-8 GB of VRAM and would be very slow if I ran them purely with my CPU. So it is unlikely that you Phone has enough RAM and enough Cores to run a decent LLM smootly.

If you still want to use selfhosted AI on you phone:

• Install Ollama and OpenWebUI in a docker container (guides can be found on the internet)
• Make sure they use your GPU (Some AMD Cards require an HSA override Flag to work
• Make sure the docker container is secure (Blocking the Port for comunication outside of your network should work fine as long as you only use the AI Modell at home)
• Get youself an openwight modell (I recomend llama 3.1 for 8 GB of VRAM and Phi4 if you got more or have enough RAM)
• Type the IP-Adress and Port into the browser on your phone.

You now can use selfhosted AI with your phone