My 4TB Apple SSD suddenly ran out of space and apps were dying all over. The startup volume became corrupt and where I should have had over 3TB free, I had 900MB. The last 2 changes were installing 14.4.1 and SoftRAID 8.0.
I rebooted to recovery and while Disk Utility still showed dozens of errors, I got my free space back after running it a handful of times which allowed me to run Time Machine to a local disk, format, and restore. (I run Time Machine to a NAS and know it takes 24 hours to restore from that).
Anyone else have something like this happen to them?