I’m not sure why you would consider the telephoto useless, that’s equivalent to a 50 mm on a full frame digital SLR. The telephoto is used a lot on my iPhone 11 Pro Max. I don’t use it as much in portrait mode as I do the one X camera in portrait mode, that gives me a more pleasing image and overall feel. As for the Ultra Wide, yeah it doesn’t look great when the ISO gets above 800. During the day though under bright sunny light conditions it’s quite amazing for a wide angle that small. However there are some workarounds when using it at night, for example I use the app called NightCap and I set it to long exposure mode and it captures multiple frames and stacks them together to give you a better quality image but does not overexpose no matter how many seconds or minutes you expose for. From there I can totally sharpen it and get a very usable image and low light but it has to be on a tripod that’s the only thing. If you’re interested in NightCap check it out because it’s a very cool app to have. You can do star trails with it you can Do you long exposures during the day to blur water like on a waterfall etc.
I believe I posted some comparisons using NightCap versus not using NightCap in the pictures taken by the 11 Pro thread, anyway I can offer my help to you as much as possible, I am a photographer and if you do you have any questions I’ll be glad to help. Otherwise enjoy your new phone.