random letters drop when typing

I currently have an Iphone 11and when typing it drops letters randomly and it will just finish the word with the blank space there, ( Hen y) and this has been a problem on multiple phone updates, So with each updated phone the problem is still there. I initially thought that it was the phone but with the first purchase of a new updated phone I thought that the problem would be gone. The fact that its there with each new phone purchase makes it seem like its a software problem. Cant wait to hear your idea.