I'm not sure League 1 is that strong tbh. Unless a promoted side has money to invest they seem to find it hard to step up - Rotherham, Plymouth, Peterborough as recent examples. Difference last time we went down is we probably had a squad better equipped for that level than the current squad (the likes of Graham, Bennett, etc and added Dack who was proven at that level).
What concerns me is, as you suggest I think, that the situation with the owners is different now. Last time they funded the club to make that quick return. This time feels like cost-cutting will be the only path and, as the squad is already weak, a quick return seems unlikely.