how to delete everything include theme settings in wp

I changed the theme folder name, since the new auto upgrade feature need CP as fold name, I have to change folder. but after folder name change. many things go wrong. delete and re install doesn’t help. I don’t know how to fix it. I hope I could delete all the setting in wp. so When i install theme, it will like first time ask me for license key and sample date. How to do that?

by the way I did upgrade from 4.8 to 5.1 . css is not working, i guess this time css is hard code location. because my theme folder name is different, so it doesn’t work. if i rename theme folder name into CP, that will give me problem above(no logo, images with wrong old folder name and so on ) .

I need help./…!!!! I don’t want to re install my wp. I have create 100+ store . …..