Actually there is a difference between a challenge and being competitive, it is impossible for the NFL Patriots to play a competitive game of football against a high school team, they can reduce the number of players or tie their left arms behind their backs for a challenging game but then it would not be according to the rules of football. I cannot play a competitive game of AoS, I can play a challenging game as long as I change the rules of the game, but to truly be competitive then that means I try my hardest to win which is not purposely handicapping myself by adding arbitrary rules. This does not mean the game is not fun when I do add rules to limit myself, just that personally playing all out competitively is my favorite, I love to pit everything I have against my enemy no holds barred and when I claw my way to victory it tastes the sweetest. Wrestling with a child may be a challenge if you do not use arms or your left leg, but being able to still pin the child does not bring about the feeling of victory (It is still though an entirely worthwhile thing I think all Dads should do)
You sound like the perfect opponent with a keen interest in tactics, and if we had similar collections or if there was an official comp system it would probably be the highlight of my week to play against you. And I do recognize that my competitive streak is not a character strength most of the time, but it is still a part of what makes me tic. For that reason I have stopped playing in tournaments and mainly play my brother, he has been the only player to actually beat me in a game of warhammer 5th-8th edition and easily of 300 games, and the first time I lost to him was a glorious moment because I held nothing back in army composition or play style.
I'm probably rambling, for anyone else reading this thread Bainbow is right and AoS can provide an immense amount of fun and challenging games, and if you really need a competitive game find someone with a similar collection who doesn't mind wicked tactics and insane synergy combos. I do feel though that unlike every other edition I have played seraphon are the top tier army in this game, basic rules or synergy and tactics they truly have risen above from the previous power armies (I always considered them around 3rd though personally)