You can't start with a wobbly foundation and then build sturdy structures on top, so:

start with Debian stable and add your cutting-edge packages on top, then watch their sources and mailing lists carefully.

There is of course Fedora. The latest is quite cutting edge, but you can choose when to upgrade to the next release. And there are security updates for older releases, so you don't have to immediately upgrade. Still, keeps you in the Red Hat universe.

This is exactly why I settled on Fedora after a few years on Arch, a few on Ubuntu/Debian/etc. Fedora is the best blend I've found. New releases about twice a year but you can skip a release if you want and upgrade every other release (or always stay on release n-1 which some people I know do).

Arch and Fedora follow the same conventions so everything on Fedora is where you expect it from Arch (this also makes much of the great Arch wiki applicable directly).

There will always be a soft spot in my heart for Arch, but Fedora is the perfect balance for me. I can't have my work machine getting broken and forcing me to read forums and mailing lists, etc.

Instead of being afraid of updates you should be able to rollback any problematic updates and be impossible to end up in a broken system because updates interrupted. The only distros offering that are NixOS and GuixSD.

That's a great start, but does not help if the data was also affected. For instance, running a new version might have upgraded a database to a newer format, or added new data with a format that the older version does not understand.

True, schema upgrades are an issue which hasn't been discussed[1]. Maybe some kind of versioning or pre-update backup in case of non-invertible data upgrade could help?

[1]: https://discourse.nixos.org/t/automatic-database-schema-upda...

I've found Ubuntu LTS to be a reasonable balance between stability and "newness," and many applications and libraries test with it.

Obviously, perfect stability and perfectly up-to-date packages are not possible, but I think Ubuntu LTS is a good compromise. I've used Arch (which I enjoy using to improve my understanding of Linux w/their excellent docs), Debian, Fedora, OpenBSD, etc and I always find myself going back to Ubuntu LTS for my work machine.

Lots of projects also put out PPAs with frequent releases for Ubuntu, which are ideal if you need the very latest and greatest. Just realize that you're relinquishing root access to every PPA you add, so be very careful whose PPAs you install, and try to limit them to the extent possible (same applies to any apt repo, obviously).

So you want stable + cutting edge?

Yes. That's the "simultaneously too fast and too slow" that all distros have to grapple with.

You might take a look at openSUSE Leap. I use the rolling update variant Tumbleweed for my laptops. But my feeling is that they are working hard to find the sweet spot between stable and bleeding edge.