It seems that about 400 point gap is normal, it is for me on lichess.com.
However, being disciplined about what moves you consider can improve your rating. Do you consider all checks and captures on every move? What about all checks and captures your opponent can play against your main candidate move before playing it? Even simple checks like this can prevent a lot of blunders. Just take a look at your blunders and see if these checks would've prevented them.
It might hard to do a check like this in severe time trouble, so 10+10 is probably better.