as a general rule, keeping your inheritance hierarchies as small as possible is almost always favourable.
A ViewModel in particular is a concept that dictates a strong coupling between the view model and the view that interacts with it. Having one view model delegate to another, although it would work, just conceptually makes little sense. It'd be enough for any developer familiar with the ideas behind view models to go "uh, why are we doing that?".
The other thing to consider is, the behaviour is similar now, but in the future it may diverge a lot, but the divergence may occur over months or years, where by "ok we'll just add this one thing." will happen many times until you end up with this frankenstein monster-esque viewmodel that doesn't really accurately represent it's actual intention anymore.
Composition over inheritance will hopefully reduce this kind of tech debt in the future, as it'll be easier to go "we should probably pass something else in instead now".
YMMV though and it might be perfectly fine, but you'll be having conversations with every new dev who looks at it, I can almost guarantee 😂