For normal web dev, any M4 CPU is good as it is mostly dependent on single core speed. If you need to compile Unreal Engine (C++ with lots of threads), video processing or 3D rendering, more cores is important.

I think you need to pick the form factor that you need combined with the use case:

- Mobility and fast single core speeds: MacBook Air

- Mobility and multi-core: MacBook Pro with M4 Max

- Desktop with lots of cores: Mac Studio

- Desktop for single core: Mac mini

I really enjoy my MacBook Air M3 24GB for desktop + mobile use for webdev: https://news.ycombinator.com/item?id=41988340