investing in that your strategy should be to find deep value in assets that the public, or in the case of Fantasy Football, your league mates, overlook. For example, many, including yourself said to avoid Saquon Barkley this year because Jalen Hurts would vulture away TDs from him and to pick a different RB in the first round.
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Well, to the keen observer they could run the numbers and see that RBs for the Eagles actually get tons of red zone touches, and that the Jalen Hurts factor would be nothing to worry about, and be able to see that Saquon Barkley possesses perhaps the best Running Back skill set and physical traits in the league and that putting him behind the Eagles O-Line would lead to increased production. This was a CMC to the 49ers type of move but being valued at the end of the first round instead of 1.1 overall. You should want players that the public undervalues. That's how you get deep value even from the first round.
There are many such players that your league mates will sleep on, but have enormous potential, if you get enough of these sleepers or potential home run swings you'll likely knock a few of them over the fence and win your league or at least make the playoffs.
There's numerous other strategies to be considered and to use, but using the correct strategies is how someone can consistently make the playoffs each year.
As far as injuries go, your team should be deep enough to withstand an injury or two and still make the playoffs. If it's not, that's on you. Only someone with incredibly bad luck whose entire team gets injured should use injuries as an excuse.