WordPress site slow

Hello,

I ran some online site tests for my site to see how fast/slow it was. I did also do Page Speed insights. Scores were low so I looked things up. I got WP Rocket and image optimization plugins.
I redid the test after and it scored really high on these tests sites but to me it feels still slow, mainly when you go to the shop and want to put things in your cart. Then the cart and checkout steps seem really slow.
Im not sure what else to do.
The backend of the site also is pretty slow when Im working on it, not sure if thats normal.
Im not very savvy with this stuff, Im just making it work as I can slowly, but it feels really slow to be able to checkout and i feel that will cost me customers.
Any insights and help is very appreciated.
Thank you

The page I need help with: [log in to see the link]