You can try memory allocation on the server, change the value in .htaccess
Your provider can help you with that unless you have direct access.
Maybe deactivate most of your plugins and speed test, then activate those plugins 1 by 1 again, retesting until you find the problematic one(s)
There are some other plugins available that will help you consolidate javascript files. Run that plugin (backup first!) test the site, deactivate the plugin.
The theme itself is more than fine. Mine runs at Google’s Page speed of 92, with a bunch of plugins running for WooCommerce, forms, sliders, SEO, etc