I suspect they'll keep creating new seasons of RS and BR and events because it sounds like MLB 22 appears to be in a bit of a delay. You'll have time.
But if you want the Billy Wagner experience, you can get that right now for free. Go to your bullpen, and replace one reliever. Then, you will be able to select a new reliever. Using the filters, find a common that is no higher than 62 rating, and make sure he's a lefty. Now, pretend he's Billy Wagner, and bring him out online. You will give up 7 homers in a row, just like if you had the real Billy Wagner card!