The ram is "unified" meaning it's a single shared between CPU and GPU, and it's "on package", meaning the RAM chips are packaged together with the CPU / GPU die, but it's just regular old RAM chips.

You can clearly see this in the shot of the Mini mobo: CPU/GPU ASIC with 2 separate ram chips packaged next to them: https://cdn.wccftech.com/wp-content/uploads/2024/11/Mac-mini...