As others have said, the best system is the one that utilizes the most out of the talent you have.
Back in my day (early 2000s) Kenton was revolutionary with their 5 wide no huddle air raid. I loved playing them because I loved watching it in action, but I hated playing against it. They had the talent to do it though.
St. Marys; where I’m from, has been running some version of the Wing-T since Skip Baughman first became head coach back in 1959. I think it’s a criteria to apply for head coach. However, that system was engrained into the community. I don’t know if it’s still like this, but the pee wee coaches used to meet with the hs coaches and do THE EXACT SAME THING. From the time I was in 3rd grade to senior year, the only thing that changed was the snap count.
Which brings me to another point, you need consistently in the program. If your Varsity HC changes every 3-4 years, you can’t instill a good system.
With that being said, I like a multi yet basic system on other sides of the ball. On offense, a mix of power and zone, so you can lean on either depending on the opponent with simple pass concepts to play action off of any of it. On defense, finding a way to have multiple coverages that base and look like the same shell. Again, so you can lean on one more than the other depending on opponent.