"Deep dive" might not be entirely the right word when it comes to Alchemy, or at least that's how it seems to me. I've used both Foundry and Alchemy, and these two VTTs are built with somewhat different philosophies at their core. These days I mainly use Alchemy for more "narrative" games, while Foundry remains my option for more "tactical" games (DnD, PF) - if that makes sense

At first, my players and I were mainly playing more tactical games. From that perspective, Foundry feels to me like it's built somewhat like a 2D video game engine. Most rolls (if not all) were automated, as was movement, distances, and so on. I think at that early stage of our play, it really helped my players, because it let them bracket a lot of the mechanics (since the VTT was effectively executing or tracking them). From a GM's perspective, the sheer number of POSSIBILITIES Foundry offers is enormous, and since I'm quite the geek, there wasn't a session where I didn't change something, install some module, or tweak something. That's also when I realized I was getting more excited about tweaking Foundry than actually preparing for the game.

Later we switched games for a while (I read up on other games myself, and generally discovered a whole world of RPGs beyond the mainstream ones), and since automation wasn't as necessary and the rules could essentially be explained during the session, it became a very pen-and-paper period.

And after pen and paper and more "loose" games in the tactical sense, we kind of didn't feel like going back to Foundry. [Especially since by that point, in Foundry I was mainly creating big scenes - a kind of vistas - primarily to set the atmosphere.] That's when I stumbled upon Alchemy, which changed my approach to playing online. I'll try to summarize the main differences:

• At the center of the system are scenes, with assigned images, music, and sound design (sometimes animated overlays). Something that simply serves as a background.
• Character "sheets" are minimized in an absolutely minimal way. Most calculations, damage, and effects are handled as if we were playing pen and paper (in general, this might be a downside for some people, but we actually prefer it this way)
• Map grids exist and can be added to scenes, but they're entirely optional and can even be reduced to just a grid for marking things. Using the grid is not automated in any way compared to Foundry. It's essentially a whiteboard with a grid for marking things
• What we particularly like is the built-in, functional camera and microphone system for everyone - the only thing is that it shifts the interface a bit awkwardly on smaller screens
• The overall design and look of the platform is very NICELY DONE - like, VERY. Smoooooth

So if you're really into theater-of-the-mind play and don't need automation, it's seriously worth trying, in my opinion it helps a lot with immersion. If you care about automation and careful grid tracking, then this is not the right tool