Fedora KDE no longer booting, likely filesystem (BTRFS) corruption

You have a problem with the log tree, you could definitely fix it by deleting.

From a Fedora live session:
sudo btrfs rescue zero-log /dev/nvme0n1p3

WARNING:

Note

Clearing the log may lead to loss of changes that were made since the last transaction commit. This may be up to 30 seconds (default commit period) or less if the commit was implied by other filesystem activity.

Short explanation

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