I’m running RetroPie on a Debian laptop and I’m able to map all the buttons of my 8BitDo Pro 2 controller; no issues at all. I was also able to connect and configure an Xbox 360 controller just fine.
You might want to try getting help on the RetroPie forums if you don’t get any luck here.
That advice is a bit old-fashioned in my opinion. There are many tools nowadays that will get you a very secure setup without much effort:
And of course, besides all these tools, the simplest way of securing public services is to keep them updated.
Rogers has been my ISP for several years and have no issue receiving HTTP/S traffic. The only issue, like with most providers, is that they block port 25 (SMTP). It’s the only thing keeping me from self-hosting my own email server and have to rely on a VPS.