My 2020 M1 MacBook Air recently died, and Apple promptly repaired by replacing the logic board, among other components. I use both Time Machine off a Synology NAS (RAID 1) and Backblaze. Both appeared to be working and the last backup date from both is several weeks ago based on the website for Backblaze and the last time a data file was touched on Time Machine.
Unfortunately, the Time Machine backup seems to be corrupt / I cannot figure out how to fix it. I've used Disk Utility to verify the APFS sparsebundle of the Time Machine backup, and it says there were errors it could not fix. Time Machine provides Error 112 ("sparsebundle could not be accessed") and I can't verify it using Time Machine (as far as I know) without Time Machine selecting the volume it cannot access (which seems strange to me -- I can browse the data files without issue).
That leaves me with restoring from Backblaze. Backblaze backed up only the home folders, including hidden and ~/Library files and folders. What is the best way to restore my (and my wife's) home folders, including key chains, from file backups on Backblaze? I'd like to keep the same usernames. I'm not sure how to move the Backblaze files over my existing home directory while its in use, and using a temporary username could mess up the permissions (e.g., my username could no longer be associated with the same UID or GID).