I would say that you should check out Fedora as your first distro. Gnome is more like Mac than KDE (which is also great). Fedora is also built off Red Hat Enterprise Linux so it’ll will prepare you for server environments and your future career. You can learn bits of both at once.
I think it benefited my career to go in that direction. I (like everyone) distro-hopped and went through a phase where I customized everything and installed a new distro every few months. But if you learn the ins and outs of Fedora you’ll be well-positioned to manage RHEL and related servers. Debian is also a good choice for that, at least in the U.S.
And there’s nothing wrong with developing on a Mac while you use Linux for server stuff. Server level code will probably run on Linux but I found that using a Mac helped me when building front-end code because macOS devs tend to be design-forward. And don’t forget that you’re building something for other people. I barely use Windows but I try to revisit it every so often to see how the other half lives.