Bit long winded but couldn't condense it so apologies in advance.
I'm not by any means saying his job was easy but saying he deserves the manager of the year award simply because he was forced to rebuild isn't sufficient reasoning in my opinion. By that logic Mark Robins should've been awarded manager of the year last year for completely rebuilding the squad from scratch under a restricted budget whilst still managing to reach the playoffs - you could also argue he was similar pressures from both the fans and the media to achieve promotion during that campaign. Also, Mowbray seemed to cope okay when manager of Blackburn last season, again arguably under similar pressures? Every manager is under pressure, if they're given a huge budget to work with and a solid core squad to build around surely if anything it alleviates that pressure.
Sunderland and Jack Ross began the season with a host of players that would walk into a host of Championship sides, let alone in League One. The likes of Matthews, Gooch, Honeyman, Maja, McGeady would've easily walked into several Championship teams at the beginning of this season. You claim he's been landed in a mess but had he really? New owners with a fresh approach, no outstanding debt thanks to Ellis Short, the biggest budget in League One, permitted to keep certain stars and provided the means to strengthen in January. Plus, if you actually look at how successful his signings have been this season, you'll find he hasn't done brilliantly with regards to recruitment. His only significant challenge when he came in was rebuilding the squad, but the vast majority of managers in League One have to rebuild their squads season after season on a small percentage of Sunderland's budget, so that's hardly a rarity.
It's not that Ross has done a bad job this season as he obviously hasn't, 4th in the league is hardly a failure. However, it's difficult to argue that if he fails at achieving promotion this season it would be classed as a huge failure for Sunderland and Ross. Not just from a footballing perspective, but also a financial one too considering they only have one more year of receiving parachute payments. You're perfectly entitled to your opinion though!