I experienced it 3 times now, that Orion either crashed or was closed regularly and on restart all previous session tabs were gone. The general issue wasn't so annoying, if there would be another way to recover tabs from the previous session. But since some of these tabs were open for a rather long time already, they did not occur in "history" anymore and even if, I would have needed to research the whole history to find all of them again.
I would recommend introducing a "safety net" for these scenarios and store a snapshot of currently open tabs regularly (like every minute or so), keeping the X recent snapshots. That way, you can offer to restore these snapshots on application start.
When opening the browser and loosing my previous session tabs (which might happen due to a crash), I expect a way to recover these tabs.
Version 1.0.0 (139), WebKit 623.1.8.0.0 on Mac 26.1 (Build 25B78)
Tahoe (26)