WARNING: DO NOT BUY A MAC M1! (see Related).
Actually, you should work on eventually getting three computers if you plan on working in cloud-native infrastructure engineering, security operations, or enterprise software development:
Whatever you do, don’t get a Mac, even if it isn’t an M1. You don’t want to learn the entire Mac ecosystem only to have to give it up for your professional work unless you absolutely must. In fact, the only situation I know of were a Mac is better than Windows or Linux is when you can’t use Linux because of business policy or you are forced to use Cisco Anyconnect (which has not worked with WSL2 for the last four years and no fix is in sight).
If you intend to play games Windows is the obvious choice for your desktop PC. If not, consider a Linux distro like Kali, PopOS, or Mint. Avoid Arch distros if you want a stable, no-hassle desktop, otherwise enjoy the pain and suffering, which will help you learn.