Loading speeds

Hi
After spending countless hours on optimizing my Customizr site: https://www.mcasien.com I am a loss and I need some advice for further progress.
I have tried everything I could think of to get my load times down, but as of now it still takes 3-4 seconds for the frontpage of my site to load.
As far as I can tell from different speed benchmarks, the load is not (only) caused by heavy media loading.
I have tried, caching plugins, jetpack CDN, cloudfire etc. to no avail. I have also spoken with my hosting provider who claims that my content is at issue.
During 6months of absence a very untalented web dev had access to the backend and it is possible that he screwed something up. Either way, I am desperate for some advice ??
Pagespeedinsights report some issues concerning:
“Should Fix:
Enable compression
Eliminate render-blocking JavaScript and CSS in above-the-fold content”
but some of these flags also appear when I benchmark https://presscustomizr.com..
Any help would be greatly appreciated