Its just another MTT, so I dont think, it makes any sense to talk about a special strategy. I have never played Sunday Million, but I would assume, its softer than other 109$ events on
pokerstars, because its the featured weakly event, which should attract more recreational players than for instance some random 109$ "Bounty Builder" or "Hot" running tuesday evening.
So most likely there is anything from world class pros to recreational players, who have satellited in, just like yourself. Or who just prefer paying 109$ to play a tournament, where they can win
real money rather than playing a 2,2$ MTT for money, that dont matter to them. Its a PKO now, so you course you need to make the same adjustments, you do in other PKOs. If you dont know, what those are, that might be a good place to start your study. Best of luck