I can only really suggest to go through the connectivity troubleshooting found here
for your first point.
If you still have an issue after this, please create a support ticket / live chat at here
with screenshots showing your port forwarding and your system files (DX diag and MSINFO) so that we can look into it and try further troubleshooting with you.
You can find instructions on how to create the files and attach them to your ticket at the links below:
You can also try manually changing the server to a different one by following the steps here
Regarding you 2nd point, you can report them to us through a support ticket, live chat, or Facebook too if you have a link to a video or screenshots showing them doing something.
Finally, regarding hit registration, the dev team would like gameplay videos from the players PoV showing issues with it so they can try to duplicate it with similar setups