Orijen... Problem with grain free food....switching food Advice

I've been researching dog foods recently. I wanted to look into feeding my dogs something better than what I currently feed. Mainly I just wanted to switch their current dry food.

I would love to feed Nulu Challenger but unfortunately it's not sold within 100 miles of my area, nor can I find it anywhere online that will ship to me for under $50 (and when I say under $50, I am referencing the cost of just the shipping and handling - not the cost of the food)! So since I can't find Challenger anywhere, I am considering Acana with grains (the Kentucky farms formula / the ocean formula). But I also am considering Orijen.

My concern is it being grain-free. I avoid grain free food cuz I try to feed food that is potato free, pea free, legume free, and soy free. Most grain-free foods have potato or pea so they're usually out. Orijen doesn't seem to have any of the ingredients I'm looking to avoid - so that's a plus. And I'm looking for something that's higher in protein than normal. But I'm still concerned because of all the information that came out a few years ago about grain free foods being linked to heart problems in dogs.

Please someone correct me if I'm wrong, but as I understand it the heart problems were caused by a lack of taurine in the dog's diet? Now this is an assumption on my part, but since taurine is naturally found in meat, I'm wondering if the dogs that developed heart problems eating grain-free foods didn't get enough taurine, because the dog food companys used to much plant based protein and not enough meat based protein?? Please tell me if I'm wrong about that. I admit I very well could be!

I'm wondering since Orijen doesn't have any plant-based protein in the formula (at least not that I could tell) and is meat heavy that dogs on it wouldn't be at risk for developing heart-related problems? I'm wondering if someone could give me their opinion on that? As I'm writing this I'm realizing this is probably something I should discuss with my vet (and I will).

For reference:
I currently feed Wellness Core Raw Rev with wholesome grains (primarily the Ocean formula but also the Original formula for variety). I also add half a packet of nulo limited ingredient wet packet topper (the toppers have one or two meat ingredients, broth, and a veggie as the only ingredients). I supplement with Wysong add life, Solid Gold SeaMeal, and Zesty Paws Aller-immune. I give instinct raw boost mixer skin and coat Health as a training treat, and other treats I provide are Stella and Chewys carnivore crunch (duck or lamb variety), and I give them honest kitchen wolfish skin chews. They don't get treats every day. I also occasionally will give them meals of fresh raw meat, organ meat, and bone instead of their kibble.

From the above I feel like they already are getting a lot of protein in their diet and I'm worried the Orijen will overload them on protein.

So any advice on Orijen, Acana, or any other brand recommendations, or advice on feeding dogs grain free and the risks associated, would be greatly appreciated!

Oh and the reason I am thinking of switching is I kind of feel like the Wellness is overpriced. It seems like I can get a better quality dog food for just $20 or $40 more. I figure if I'm already willing to spend a fairly premium price for an 18lb bag of Wellness, what's another $20 or $40 for an even better quality food. Maybe that's not the best reason for switching but I just want to insure I'm giving my dogs the best I can.