Can I sort my spaces by grace period instead of by due date?

Yes. By default, items with grace periods in your work spaces in Onboard > Logs sort by their due date. To sort them by their grace period end date instead, turn on Sort Spaces by Grace Period on the Setup > Tenant Preferences > Tenant Preferences tab. It's a tenant-wide setting, so it changes the sort order for everyone, not per user or per role.