Buy a smartphone with good camera or buy a camera and a phone?

I’m due an upgrade of my phone.. have had the iPhone 6s for 3.5 years and it is becoming so slow, bad battery life and camera not satisfying me. I am an Apple lover – I use an iPad and my past two phones have been Apple. However i wouldn’t strictly rule out a change. I’m into art and I need a good camera to take photos. The one on the 6s isn’t really doing it for me anymore. I’m not sure if I should get a more expensive phone with a good camera or just upgrade my phone to a slightly newer model and buy a camera. I’d say the iPhone 11 is top of my budget range and maybe stretching it at that. What do you think I’d be best to do?