That bug does sound bad, but it is not clear to me how a BTRFS specific bug relates to it supposedly being more difficult to recover (or backup) when using whole-disk encryption with LUKS. It seems like an entirely orthogonal issue to me

What makes recovery and backup a nightmare to you?

I’ve been running full-disk encryption for many years at this point, and recovery in case of problems with the kernel, bootloader, or anything else that renders my system inoperable, is the same as before I started using full-disk encryption:

I boot up a live-CD and then fix the problem. The only added step is unlocking my encrypted drive(s), but these days that typically just involves clicking on the drive in the file manager, and then entering my password. I don’t even have to drop into console for that.

I am also not sure why backups would be any different. Are you using something that images entire devices?