Thanks for letting me know about the steps you've taken to resolve this. It can help me identify which other resolutions to test out. I'll be your guide through ensuring your PayPal account will be connected to QuickBooks Online.
The troubleshooting you've performed can generally fix the inability to connect Paypal into the program. Since none of them work, I'd recommend giving us a quick call. Our dedicated team can securely access your account and has the necessary tools to double-check what's causing this to happen.
You can also copy the link of our thread in the address bar above and give it to the specialists. This way, there isn't a need to re-explain the situation.
Our most-up-to-date contact details can be found here:
By taking this route, you should be able to connect your PayPal account into QuickBooks Online in no time.
Don't hesitate to let me know how the call goes. I'd be here to help you, anytime!