Difficulty typing on Iphone because of fat fingers
Practice makes perfect, but the real differentiator between people that struggle to learn to type on glass and those that become proficient is the mindset when you learn.
I would encourage anyone struggling with this to give themselves a huge window to learn. Play around with the keyboard for 5 minutes, don't worry about your fingers covering the letters.
Also, experiment with the voiceover and assistive touch settings to see what different input lag settings do and also changing the entire meaning of a tap (with voiceover) does for your concept of touch control.
Also, when playing - see if you can place your finger in the empty zone between three characters (two on one row and the key below the gap). Plop your finger down but don't lift it. Then pivot it gently, rolling on the fleshy part of your finger and see how the contact area changes as you rotate your finger. You can drop your finger where you think the letter is and then adjust before lifting.
After playing a bit, you will quickly get better as long as you don't get too frustrated with yourself. Just as learning to ride a bicycle can be hard initially, this too is a fine motor skill you need to practice.
I've never met anyone that couldn't learn to type due to physical size of their digits. Of course nerve / control / other physical limitations such as missing bones or digits is an entirely different situation than being used to seeing where you tap and/or not training up a new skill.
If you have an issue typing, there are now switch controls, voiceover, assistive touch, accessibility options galore on iPhone and iOS.
If your issue is attitude or feeling it’s not worth learning a new skill since you prefer a keyboard you can connect a keyboard or buckle up and start learning a new skill.
Don’t allow yourself to think you’re too impatient, too old, too young, too busy, too frustrated or just don't care to learn a new skill. There's nothing wrong with any of that, but if you give yourself a few days to adjust I think you just may start to like the keyboard or at least reach a level of peace and possibly comfort with how the touch detection works.