Try troubleshooting Safari extensions ..
From the Safari menu bar click Safari > Preferences then select the Extensions tab.
Turn that OFF, quit and relaunch Safari to test. If that helped, turn one extension on then quit and relaunch Safari to test until you find the incompatible extension then click uninstall.
If it's not an extensions issue, back to the menu bar, select the Privacy tab.
Click: Remove All Website Data
Now select the Advanced tab.
Select: Show Develop menu in menu bar
Now click Develop from the menu bar. From the drop down menu click Empty Caches.
Quit and relaunch Safari to test.