TL;DR depends on your gpu.
Some monitors below HDMI 2.1 support the early version of freesync made by AMD, while others support a fragment of what became 2.1’s VRR. The former is supported only by AMD, while the latter by both AMD and Nvidia (Pascal and upper with latest drivers). If you have the former, the monitor is probably not compatible with DP’s official adaptive sync, so Nvidia won’t work even on DP.
But… Even if you have AMD, due to a bug in the driver, if you have a Polaris GPU it might not detect the vrr capability over HDMI (but will over DP). I know for sure that RDNA 2.5 cards support it, in theory it should work even for all Vega and Navi GPUs, but I haven’t tested it.
Unfortunately it requires vulkan (it says 1.3, but because vulkan is based on extensions so it probably doesn’t require the full 1.3). So if you have the Intel GMA 950 that’s in the motherboard for your Pentium 4 HT is not supported. But I’m confident that an AMD HD 6000 from 2010 with the Mesa driver “terakan” is enough to run it. And theoretically one could implement vulkan even for an HD 2000 from 2007, but it’s an unreasonable effort.
If they made an opengl backend, you would be golden, as the Mesa driver i915 implements opengl 2.1 for the GMA 950, and it’s definitely enough to run an editor
P.s.: and I sure did not spend the last 30 minutes looking up vulkan hardware