If you're after security (hardware and OS) your Macbook is a very solid option. You can do only better with fully abandoning everything but GOS and get a Lapdock or monitor + periphery for your GOS Pixel. The Desktop mode came a long way and might already or at least soon be usable if you don't depend on specific Desktop apps.
For privacy and potentially anonymity obviously Apple doesn't cut it with their proprietary code and telemetry ignoring your privacy settings. Same is true for Windows, so you're best off again with GOS, but for a Laptop a good Linux Distribution will do. Looking around this forum, you'll mostly find Linux Mint, Fedora, Silverblue and Secureblue recommended (each one adding security and inconvenience). Maybe start with out of the box Linux Mint (more consistent and sustainable) or Fedora (more secure and MacOS like) to get the hang of it.
If you want a Laptop, usually any good common hardware will do, especially if it's a year or two old. But the very best Linux compatibility usually is found on Thinkpads and nowadays Framework Laptops. Battery life mostly depends on the battery size and CPU efficiency (AMD usually does better, but newest Intel chips work too). Obviously don't get a gaming Laptop with GPU if battery life is what you're after. I'm personally using the Framework 13 AMD 7040. It's a bit overpriced and old looking, but gives me the highest repairability and modularity on a small laptop. I can also put different Linux OSes (and Windows for gaming) on the SSD expansion modules and run them air gapped from each other, it's more security, compartmentalization and simplicity at the price of performance. But that's a very niche setup.
So ask yourself:
- Can you run everything on GOS? Do it!
- Do you need security and are willing to sacrifice privacy? Stay on MacOS.
- If it's the other way around, check your budget and research online for devices with good Linux compatibility.