Solutions for when the phone's function menu won't open!

1: I installed a launcher modification app on my phone, and later accidentally changed it to 15 icons. Even after deleting this app, the problem wasn't resolved. I installed another launcher modification app, which restored the original 3×3 layout. After that, I deleted the launcher modification app, and after rebooting, the menu couldn't start. At this point, it's like the interface mapping is broken and it won't open. Installing the launcher modification app again doesn't help. Then, if you install a directly installed font and restart, it can solve the problem, or you can factory reset the phone.