Take our apologies for the delay in answering.
Only 2 sources from the links (on the screenshot) with high impact are coming from our theme/core. To improve others you can disable those plugins (which will disable the functionality of them) or try to use any of Cache Plugins to minify css/js files in one. For example W3Total Cache (free, https://premium.wpmudev.org/blog/w3-total-cache-settings/ ), WP Rocket (paid), or any others.
GTMetrix changed its testing system, and all the sites that had A, B scores get C, E or F. Try to test your site here – https://tools.pingdom.com/ Google Pagespeed (and now GTmetrix) always scores with 20-50 points mobile performance for 99% of websites built with WordPress.
However, our team working on a big update that will include a huge improvement in speed, it will be released within 1 month.
