It’s been a few months since I played around with the online Sketchup, but I’ve just tried to do something and it is behaving very odd.
I can’t use the keyboard commands, and it actually deletes things I have drawn when I use the “L” command!
I also cannot input dimensions for commands such as “Push/Pull.” I can give a dimension for drawing a line, but when I then try and type one for P/P it doesn’t work.
What browser are you using? Edge? There have been numerous reports of broken keyboard shortcuts due some updates made by Microsoft. You could check to see if updating the browser helps but most users have found that switching to using Chrome or Firefox solves the problem.