I was on Ubuntu for a year. No major issues, although I used the interim releases, which are supposed to be less solid than LTS. Then, a couple of months ago, I decided to switch to Fedora, just out of curiosity. Many people stated how Fedora is rock solid, Fedora is the new Ubuntu, etc. First some rpmfussion updates broke mesa, then the ostree update broke Flatpak, and recently there was a broken kernel 6.3.11 update that affected some AMD users. A few days ago, I updated my kernel to 6.3.12, and I got frequent freezes on boot. Other users are also reporting such issues. So now I boot with an older kernel. Which is not optimal. There is no LTS kernel on Fedora, the old kernel version doesn’t receive security updates. Was it always like that, or it’s an unusual bad phase.
It is unfortunate, but the reasons are discussed in the bug report: https://bugzilla.redhat.com/show_bug.cgi?id=2113005#c52
tl;dr: Fedora cannot just build an updated shim because it has to be signed by Microsoft for secure boot support. Microsoft added a new support requirement that had (maybe still has) not been added to the kernel. Shim is not touched very often, so any distro that is using an old one that was already signed would be unaffected. I don’t know why Fedora didn’t just downgrade to one that is unaffected (I’m assuming they had compelling reasons for the upgrade in the first place), from a distro perspective that is their only option to fix the issue.