A cheap DP-HDMI dongle makes all this go away. As long as VESA doesn't behave the same way, anyway.
You can even get cables that are DP on the input and HDMI on the output with minimal bulk.
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.
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...