I ceased the experiment with Google pagespeed mainly because I changed hosts. The hosting I have has Cloudflare as a recommended default. Cloudflare has been updating most of the time I have been using it, so I can’t really report on whether it is helpful or not. I have been deleting extra plugins and themes, as a precaution against hacking, although it is still a concern.
If you are just starting out with WordPress on your own hosting, what I would do if starting over, is to sign onto a hosting site that specializes in WordPress platform and that promises reliable security.
Site security has been a big learning curve for me, and probably for many other WordPress bloggers.
The choice of theme and the use of added plugins are both factors in how fast -or slow- your blog will be. Another consideration is the image size files. It is good to reduce the image to resolutions and sizes that are optimized for the web. If you have Gimp (free program), you can export your files and choose the quality of the file, otherwise go ahead an use an online optimizer.
Here are some choices for image optimizing: