Hi residual and welcome
One thing I didnt see. I assume you are using homegroup for networking. If so you are using IPv6. IIPv6 causes exactly this type of problem. It has been shown to sometimes cause random drops, slowdowns, dl problems, and oh so much more. I have a gut feeling that this might be the issue. If so it is fairly easy to resolve. Go to network and sharing and setup a new network using the work model called workgroup. It uses a differen IP protocol and is much more stabile. once setup and configured you can disable ipV6 and kill the homegroup.
I have seen this problem more than 100 times and it usually if IPV6.
Let us know how it turns out so I can add case number 101 <g>
When I try to create a new network connection I get the following error:
Connection failed with error 651