If money was no object: max-spec OSX laptop for coding, max-spec Win10 laptop for gaming. More realistically I'd really get a conservatively priced OSX laptop and a just-off-bleeding-edge-spec Win10 desktop for gaming. I like my dev rig to be mobile but gaming can just happen at home.
If I could only buy one machine for everything including gaming, I would have to pick a Win10 machine with WSL for coding. There are a lot of crossovers in terms of specs - both dev and gaming like SSDs, plenty of RAM and CPU. It's just the GPU that needs extra investment for gaming.
The one approach I've not really tried is a linux machine. So if I was just planning to do development and money was tight, I'd consider giving that a go. There are a lot of relatively-cheap laptops that will happily run linux for dev purposes.