Actually have a good Internet line. Usually in Fortnite (20-30 ping), but for a few days he is running at 70+ all the time.
What could it be?
Start a package tracking to the Fortnite servers, then you'll see where the big delay is.
Otherwise uninstall Fortnite, that's always possible.
This has nothing to do with this cancer of the company called Fortnite.
Either there's a bandwidth restriction from the provider or more likely someone else is using the internet at the same time as you. So for example Netfilx, Youtube etc. As against then helps only to increase the bandwidth or make up who uses the internet extensive.
Do you play over a Wi-Fi connection or over a LAN cable? Try it with a LAN cable.