Jumping in here... I am gonna have to respectfully disagree about 16GB being the sweet spot. Honestly, if you are planning on running things like the Phoenix Lighting Mod or some of the more intense script-based overhauls, you are gonna hit a wall faster than you think. I remember trying to push a heavy modlist on a mid-range machine last year and the frame-time spikes were just brutal because of VRAM and system memory bottlenecks... it basically made the game unplayable in Novigrad. I would suggest being a bit more cautious and aiming for 32GB of RAM from the start. It is not just about the game itself, but how those mods interact and cache data. Something like the Lenovo Legion Pro 7i Gen 8 with RTX 4080 and 32GB DDR5 is a much safer bet imo. Also, make sure to check the TGP on the GPU. Some laptops throttle the power which kills performance in modded scenarios. If you want a beast that actually handles the heat, maybe look at the Alienware m18 R1 with RTX 4080. Just be careful with the weight tho, it is basically a brick.

For heavily modded Witcher 3, you're going to want something with serious GPU power. I've been running it on an ASUS ROG Strix G16 with RTX 4070 and it handles everything I throw at it. The visual mods like HD Reworked Project and lighting overhauls can be really demanding, but I'm getting solid 60+ fps at 1440p with most settings maxed. The 16GB of RAM helps too since some of the larger texture packs are memory hungry.