I fully agree. Trying to use the browser version of ultimate guitar on a 6 inches smartphone is a very frustrating experience. I remember subscribing to the pro version of ultimate guitar about 5 years ago when the app was a must go and in my opinion, it's just been downwards since then
I use it because it does have a lot of songs. The search on it is the worst and the UI has its own back button that is not easy to use. Most good apps on Android let you use the devices back button.