Ironically, prior to 2008 the process name was backwards the other way, for example 130nm process usually has something like 70nm gates.
It’s always really just been a marketing thing anyway, since the possible density of a given logic unit in a given manufacturers process will differ due to a huge number of factors.
These numbers stopped having anything to do with the sizes of things a long time ago.
The "2nm node" is a marketing term to indicate its placement relative to previous iterations and competitors.
The reality is that process nodes are complicated and capturing it with a single number would be a bad idea. You could go for raw transistor density which would be better but it misses a lot of the nuances in design.
If you take the square root of that...you pretty much end up with (modulo a linear scale) the existing nodes.
That gets you size. You then need power and speed, which are a bit trickier to compare without a standard/reference device.