Best kernel recommendations? Mainly for extremely long running (2+ years) SaaS applications. Stability overall. Is running a handful of docker containers and some binaries.

Linux LTS if stability is the most important. Realistically, "normal" Linux works for for it too, not sure you have to care as deeply about what kernel you use as you seem to do.

On my desktop I use linux-cachyos-bore-lto which seems to give me a slight performance boost in compilation times compared to the regular kernel, but I've had at least one crash that I've unable to attribute to any other specific issue, so could be the kernel I suppose, I wouldn't use it on a server nonetheless.

FreeBSD is touted for long running and stability.

For desktop use, I find that being on the latest stable kernels is best because you get things like recent AMD graphics drivers and support for recent hardware and laptops. I’m in an arch-based distro and my kernel updates all the time. I’ve never had an issue. The stability benefits of LTS seem completely useless in comparison. Just my opinion though.

If you’re running applications as in a server that’s an entirely different discussion. I have been assuming we are talking about desktop users who are not serving anything.

E.g., if I go out and buy a 2026 Panther Lake laptop with a new WiFi 7 chip or what have you, I’m going to want a distro with the latest kernels so that I don’t have hardware issues. If I install the default Ubuntu download it’s going to almost certainly have problems.