If you actually test speed using W3TC vs. other caching plugins, you’ll find W3TC is by far the most complex to setup + one of the slowest.
Instead, try WP Super Cache with one option - enabled - for good speed. You can go one step further + setup mod_redirect caching for more speed.
As for the WPT report link, here’s my take.
Asset #1 + #2 are hosting problems. Fix - change to high speed hosting.
Your site is running HTTP1.1, rather than HTTP2, so switching to HTTP2 will provide highest speed.
Asset #19 is a 404, so as soon as this asset is hit, one browser thread is hung for rest of session, which drops site speed by 20%. With HTTP1.1, most browsers use 5 threads, so each hung thread decreases total threads by 20%. Very bad.
Fix - add the dot-dd.gif file to your site (even if you have to create an empty/zero length file) or remove references to this file.
Fix these items + your site will serve pages very fast.