weird touch behaviour on my iphone

Hi

recently my iphones been going a little nuts with its touch input, random characters would input when typing and I would find it hard to type. Usually when this happens i just clean the screen and its fixed, but this time it just keeps coming back.

The weirdest thing, is that when texting sometimes, it seems like i can activate a key input without seemingly even touching the sceen! My thumb will hover what must be half a mm from the screen and it will still manage to activate the letter - sometimes, it will activate a letter that my thumbs no where near!

Im on an iphone 8 with latest software, and have rebooted, but it still happens.

Is my screen on the way out or something? I had it replaced at apple what must have been less than 2 years ago so id hope it would have more life in it.

any help would be much appreciated

thanks

Nick