Is suspend working reliably on Linux for MacBooks?

That's a global issue with Linux. There are people having problems with Linux sleep/suspend on a wide variety of makes of laptops, include Apple's. But not everybody is having a problem with every make of laptop which means it's either a distribution issue, user error, or some combination of the two.

This is not a global issue with Linux. My Librem 15 has 100% reliable sleep. Devices designed for Linux work flawlessly.

Google "linux laptop sleep suspend problem" and have fun reading all the problems people are having with sleep/suspend with a variety of makes and models of laptops. Meanwhile, sleep/suspend has been worked out for MacBooks, for some time actually. Presumably even on the M2's since that's the machine Linus uses for his development.

The suspend problems only occur on hardware not designed for Linux, which is most of the available hardware. Therefore I'm not surprised that it affects a variety of laptop models. Meanwhile all devices specifically targeting Linux have a reliable suspend.

The same thing is happening with Macs: Hardware designed for MacOS has a reliable suspend on MacOS.

Suspend and hibernate have worked on a variety of laptops I've owned over more than a decade. You can also easily build a custom desktop and never run into issues with either. Issues with suspending stem from manufacturers' bespoke components, firmware, configurations and/or non-standard handling of any of those.