Which further emphasises what I mentioned earlier, something on your computer (firewall or av) is blocking Aristois from correctly working. This is something you have to look into, I cannot help with it.
Donations are instant, as long as you provided the correct information. You will receive an email to the address you entered that has instructions how to get the donor perks. You can also read here
You cannot install it to "vanilla", as Aristois must run either Fabric or Forge. Since other launchers don't use the default file configuration, you must use it as a mod. Follow the modpack instructions
