Don't wait for 32GB of RAM. If you need more than 16GB, look again at the XPS15 from Dell, or one of the other Windows Notebooks you mentioned. I would probably go with Lenovo.
If you can live with 16 GB and like macOS, then the Macbook Pro 15" is a good choice, but get at least 512GB SSD if you use BootCamp. In a Parallels VM you are restricted to 8GB RAM (Parallels standard version that I use myself).
If you spend most of your time with the Macbook in BootCamp, then I really think that Apple notebooks are a waste of money nowadays. This was not so bad up to 2015, but the new Apple notebooks are not recommended for exclusive Windows use, in my opinion.