A cheap DP-HDMI dongle makes all this go away. As long as VESA doesn't behave the same way, anyway.
55" monitors with DisplayPort do exist but they are only a selected few and seem to cost 4 times the price of a 4K TV.
So 4K is still pretty much a luxury that I will just ignore for now.
You can even get cables that are DP on the input and HDMI on the output with minimal bulk.
Not for the past few years. Although DP 2.0 has been 'released', there are no products actually shipping with it, and in practice DP 1.4 is the latest standard. DP 1.4 can't transmit 3840×2160 at 4:4:4 144 Hz without Display Stream Compression (DSC). HDMI 2.0 can.
Here's a GPU with DisplayPort 2.1 https://www.mindfactory.de/product_info.php/16GB-Sapphire-Ra...
Here's a Display with DisplayPort 2.1 and higher Resolution&Refresh Rate than you specified https://www.mindfactory.de/product_info.php/57Zoll--144-78cm...
[1]: https://tftcentral.co.uk/articles/when-is-displayport-2-1-go...
I normally run it on 120Hz over DP, but it will work fine over HDMI 1.1 at 60Hz. My (5+ years old) TV runs at 1080p/120Hz just fine too.
https://en.wikipedia.org/wiki/Mini-DVI
Which is cool, but not quite as cool as micro-DVI, which they used for exactly one MacBook Air generation before mini-DisplayPort arrived on the scene
https://en.wikipedia.org/wiki/Micro-DVI
Edit: you are right though. I just pulled up pictures on early G4 variants, and there is indeed full-size DVI. I completely forgot that.
Even DVI had HDCP though, so it too was flawed :-( https://en.wikipedia.org/wiki/High-bandwidth_Digital_Content...