How old is the device you're on? Are you running other things in the background? I ask because I'm not experiencing that at all on my laptop. I was told by one other person that if they were streaming video while working in NG it caused lags.
Discussion
A pretty high-end gaming laptop but you're right, it is 2.5 years old and the processor is heavily worn out from playing games.
Not running anything significant in background.
Ok, what browser are you using? Chromium browsers have the fastest javascript engine, with Chrome being the best followed by Edge, then Opera/Brave. Chrome is significantly better than the others.