The website seems to do the following for a millisecond before it is fully loaded:
Loading my website (www.BallsOnly.nl) (blogwebsite) incognito without JavaScript does not load part of the CSS. Pictures won’t load without JavaScript anyway. There are weird things in the head (like a div). Seems (partly) related to the caching plugin.
As a result, Google does not load the website properly on mobile and the website does not seem to be usable on mobile. (according to Google Search Console)
See attachment for screenshot: