When I told my previous airline boss that working 6 on 2 off and starting on earlies, finishing on lates, was so fatiguing, he said you don't work that pattern as much as you think you do. (We did, so I left).
I once had a discussion with my C.P. We were rostered the minimum 8 days off per 28. It didn't matter if there was any work to do or not, only 8 days off. Sometime there were stupid days of positioning, single sector flight, taxi home. A very long day to achieve very little; but it had to be a duty day: or endless SBY's. I suggested that, as Ops worked 4 on 4 off with late & early shifts and a more restful duty roster; the more so considering they were not locked in a tiny box, the pilots might also deserve a shift pattern of days on/off.
"You don't work shifts. Case closed."
We did, so I left.