inconsistent loading page from a location to another

Hi,

My website has been working well for over a month with no issues since i moved to private hosting with upcloud. Since last Friday, i have been experiencing inconsistent loading times. Sometimes a page would load in 1.5 second then a min later it takes 40 secondes

I Also noticed that loading page time may differ from a device to another

Moreover everything seems to work fine when testing the website on platforms such as gmetrix or google spaceflight with B grade and more. All this said, these platforms only connect from Europe or US. I connect from Tunisia. So may be the issue is just local.

I’m clueless as i don’t identify any pattern here.

Nb: I have already tried deactivating all plugings and it did not ameliorate the situation

The page I need help with: [log in to see the link]