I have a Logitech K800 from 2017. It is having huge problems with random lag when I try to type something. I was looking at the Logitech K540 which looks like a direct replacement based on the keyboard layout. BUT Amazon reviews state it has a huge problem with lag when typing. What is up with that? I need the bottom 25% or so of the keyboard to act as a handrest as that is what I am used to all these years. Every wireless keyboard on Amazon is a Logitech and none of the others have the K800 design. Recommendations? Price doesn't matter.