Hm, yeah that’s pretty rough.
The item taking the longest to load by far, and sometimes failing, is from
That appears to be what’s pushing everything back.
In your site’s source, it’s coming in as part of
<script src="https://contextual.media.net/dmedianet.js?cid=8CU38M7CS" async="async"></script> so no clues there unfortunately.
Do you know what’s adding that?
If not, please attempt to disable all plugins, and switch to the default Twenty Twenty theme. If the problem goes away, enable them one by one to identify the source of the problem.
Also, we have some general recommendations at https://wordpress.org/support/article/optimization/