The only reason I recommended this is because Forge has issues with OptiFine and OptiForge fixes those issues. Most modpacks run like trash without OptiFine, so that is why I said that. It was just a recommendation from my modding experiences with Minecraft.
Try removing OptiFine (and OptiForge and MixinBootstrap if those are in the mods folder)
If you are still having issues, please post an updated log.
RandomPatches has a dependency Cloth Config API
Make sure that every mod you have installed is the correct version that is compatible with the Minecraft version you are using, and check to make sure you have all the required dependency mods installed.
First go to the view tab in File Explorer and make sure File name extensions is checked
Right click on the .jar file and click Open With > Choose another app
A list of suggested applications will appear. Click on More apps.
Scroll all the way down and choose Look for another app on this PC
Locate the java.exe file. It is usually located in Program Files\Java\Java version\Bin folder
Select the application and click OK button to set it as a default for .jar files
Now you should be able to double click the .jar file and run it as intended
No, only download forge from Minecraft Forge and only download Java from Java.com
These are the official sites for each file and using other sites could cause you to unknowingly download malware.