Improve my mobile and desktop website performance

My website doesn't score well when it comes to performance/speed (check screenshots attached). I'd like performance in the green zone for both mobile and desktop. But I'd like to it done sensibly without changing anything about the actual visual frontend of my website.
I would like particularly that my shop page loads fast and efficiently, but obvs homepage as well.
URL is anjalobert.co.uk, and shop URL is anjalobert.co.uk/shop