Magento 2 Site Speed Optimisation

Hi I am looking for someone who can Optimise Magento 2 Site , the site had a recent change to template and since has dropped off in speed it looks like Images need to be resized and server configuration may need to be looked at as this may have changed , I am looking for fixed price and fast resolution for this task , any experience with Nexcess Magento 2 Hosting will be benificial.