You don’t have to hack the firmware you just have to use a hacked driver. And what do you mean external transcodes are limited to 720p? I can watch 4K at work streaming from home on Plex. I also use my 1660 super for reencoding using tadarr and literally just tonight I was working on switching from Blue Iris to frigate and using my video card for AI. Also I do believe three is the limit of transcodes you can do on a consumer card not one.
The amount of transcodes your video card can do is dependent on the video card but I would suggest Nvidia. I have a 1660 super in my unraid machine and it uses a hacked driver so it can do more than it’s usual number of trans codes which is limited by Nvidia to make you buy quadros. Usually I think it can do three or four I don’t remember but now I really don’t know how many can do I have had 8 simultaneous streams all going outside the house to different devices and the system didn’t break a sweat.
Most of the services I access through Open VPN installed on my router but I do have things like vault Warden, next cloud, mesh Central, and a few others exposed directly. They all require username and passwords to get into and I use almost everyday and wouldn’t know how else to use them in my workflow if they weren’t exposed directly to the internet.
I cringe at the thought of putting pi hole on a gaming PC, you must live by yourself and have nobody else that relies on the internet. You shutting off your main gaming PC would shut down the internet for the whole household.
I don’t relay anything through plex servers, I can easily access my media from anywhere without their help. You don’t seem to know what you are talking about.