1) Go to the category that has subcategories and choose Display type > Subcategories https://prnt.sc/7NdUs6ezMIGU
Do that for every category where you want to show subcategories only.
2) Check the server error log. What error do you get there after such menu savings?
3) Go to Appearance > Widgets > Shop sidebar > edit Product categories widget and choose the custom order instead of sorting by name https://prnt.sc/CzHP4tOGWRAK
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.