Courspress front end VERY SLOW

Hi there,

When a user takes the course in the front end, it's very slow.
Especially when clicking through from, for example, Work to Units
Or Units to Notifications.

Best time so far was 2:30 minutes
This is terribly loooong.

The same happens when registering or logging in.

I've tried your suggestions here:
https://premium.wpmudev.org/blog/5-quick-ways-to-speed-up-your-wordpress-site/
None of the options or combination of options even improves loading speed (not even 5 seconds)

Please help