Soft-on light effect?

Hi all. I’ve been using home assistant for a while to get used to it before moving into our new house. Now that time is upon us and I still have a question I never found the answer to.

How do I get the soft-on/off effect that makes a basic light turning on and off feel smart?

Currently I am hoping to fit every light switch with a ZigBee smart switch behind it, allowing traditional controls as well as smart controls but that seems to get me the binary toggle. What would really make this new home feel incredible is when I tap a switch I get that half-second fade-on effect, or a gentle up/down fade as I move from room to room. You know, like the sci-fi movies we all want to mimic!

So I come to you with this question, how do we achieve this effect? And for bonus points, how can it be achieved without cloud connection or delayed responses. Ideally I don’t want a fade-on/off routine triggered each time I hit a light switch, I would love this to be handled as close to the light source hardware-end of the chain.