vue electron builder blank page - vue.js

Question

How I came to the problem:
I setup an project like this:
https://www.smashingmagazine.com/2020/07/desktop-apps-electron-vue-javascript/
until it came up to the coding part, there I added custom stuff. Created Components and so on. Everything works fine in serve then I want to build it.
What I expect as outcome:
App working as in serve mode
What I got:
blank page
What I've tried to fix the problem:
change a wide range of path urls like:
win.loadURL(url.format({
pathname: path.join(__dirname, '../public/index.html'),
protocol: 'file:',
slashes: true
})) // with different links passing different index.html files (raw vue build, electron build and public)
win.loadURL('app://./index.html')
win.loadURL(`file://${__dirname}/../public/index.html`) // aswell as the variation without file protocoll
Problem is I dont get errors. If I open developer console at the end of the building process by the menu bar it says, that I have to reload the page that the console is attached to the program, when I press reload, nothing happens.
Any suggestions to go further?
edit: here are my dependecies:
"dependencies": {
"axios": "^0.20.0",
"core-js": "^3.6.5",
"jquery": "^3.5.1",
"vue": "^3.0.0"
},
"devDependencies": {
"#vue/cli-plugin-babel": "~4.5.0",
"#vue/cli-plugin-eslint": "~4.5.0",
"#vue/cli-service": "~4.5.0",
"#vue/compiler-sfc": "^3.0.0",
"babel-eslint": "^10.1.0",
"electron": "^9.0.0",
"electron-devtools-installer": "^3.1.0",
"electron-icon-builder": "^1.0.2",
"eslint": "^6.7.2",
"eslint-plugin-vue": "^7.0.0-0",
"vue-cli-plugin-electron-builder": "~2.0.0-rc.4",
"webpack-cli": "^4.0.0"
},

Answer 1

So after many hours of struggling because I couldnt open a working console I found a tool called Debugtron. After a bit of optimization it throwed the error:" createProtocol is undefined ".
The autogenerated background.js missed the line:
import createProtocol from "vue-cli-plugin-electron-builder/lib/createProtocol";