Like yourself I'm graduating from Koikatsu and Honey Select 1\2 .. give VAM a chance -- but you'll need to change your mindset a little. It's like a sandbox of tools which you can customize. Once you get the hang of it you'll never go back to those older apps\games.
Like some mentioned above, VAM isn't really a game.. it's more like making your own pornhub with your own actors. And you're the director.
The thing with HS and KK is that you're stuck with the animations from Illusion.. and even if you add new characters, its the same set of animations and levels.
(Which gets boring IMO) VAM doesn't have that limit as the community can pretty much do everything from updating the code to animating new scenes. etc etc
I couldn't make any smooth gifs.. but this is just an example of hot swapping characters without leaving the "scene" and don't know if you can notice the realtime hair. Unlike the plastic hair that clips the floor in HS2 for example
Oh and VAM let's you customize facial expressions.. of course you need to install the plugin. That's Ada (from RE2) looking mad if you can notice.
Another big plus with VAM -- u can add your own lights .. so you can control the mood. Unlike HS2 which just gives you these preset post process stuff.. which still makes the scene look awful.
There's a whole other bunch of stuff like being able to move the actor's hands, legs while in the "action" .. but there's just too much. You'll need to discover all this by playing around in the VAM sandbox.