I've tried Zed several times like this and it continues to lose data.
While there was a bug where the session was lost when updating, this was fixed years ago.
Are you sure? I believe Sublime preserves all your unsaved tabs even on update.
burned once, twice shy; i wouldnt update without spending an hour making up names for random junk files
Sublime also saves a backup of its state files next to the state files in your home dir, so you can restore in case anything ever goes wrong (e.g. bugs in the new version).
The .sublime_session state files are JSON, easy to read for a human.
> spending an hour making up names for random junk files
That is completely unnecessary. You can just backup the '.sublime_session' file that contains all that before an upgrade if you are worried. Sublime already stores all its state in 1 file; manually spreading that across N files seems unfun busywork. A quick web search reveals that by the way.
(I perpetually have 40 Sublime windows open, each one with tens to hundreds of tabs. My 'Auto Save Session.sublime_session' is 70 MB.)