iPad screen sensitivity variances

My iPad screen seems to lose sensitivity at certain times and I cant get a response to what I am asking it to do. This is a particular issue when using the screen keyboard, often if I am using the outlook email app or the Word app. It can be absolutely fine but then other times it just doesn’t recognise my touching certain letters. Also, on occasion there seems to be a big time delay between what I am typing and the letters appearing on the screen. This happens most in Word.

I can’t be sure it is app specific but I have just struggled to type an email in Outlook - having to revisit and retype much of the text due to missing letters etc - but it is now typing perfectly in this chat box!

I have checked that all possible system and app updates have been done and it hasn’t helped.

Thanks for any help anyone can offer.