A lot of things have to break right for any team to win 12 games (or more). I think skill personnel-wise on offense they're in better shape than a year ago this time. And I believe the defense is going to be very good.
It is, of course, the OL that is the big question mark. If at least Whitworth and Havenstein are good I think the interior will sort itself out. Corbett getting abused by Donald one-on-one in drills and a scrimmage doesn't bother me because of course he does that to anyone. I like Blythe at center personally. Going to be issues there on the interior early on but it is what it is. Cannot be worse than the first 6 games of 2019...
While the division is tough I don't know that it's tougher overall than a year ago. Arizona may be better but I do think the 49ers take a couple steps back. As FootballOutsiders has said, teams that take such big leaps forward in one year almost always have a "correction" the following year. Rams need to go 4-2 in the division.