New rank above Diamond

I have been playing ranked for about 150 hours total for 5 seasons. First two seasons I was Gold, then Plat, then Diamond for the last two seasons. One thing I noticed was there is HUGE SKILL GAP between players in low-Diamond. A team you may find in low-Diamond lobbies might be strolling around the map and waiting for the zone with 150 dmg to their name with no defensive legends whatsoever, or an absolute kill squad with 2 flankers. I am not even talking about aim, the gap is in the game sense and fighting approach. Is it because of boosted players? Could be, I don't know. My suggestion however is to add a new rank division above Masters, so Diamond is not this crowded and asymmetrical.

Problem I have is that I am not a very experienced player, and I find it quite hard to determine what fight to pick because of this asymmetry. One entry, all three of them are looking at you; in another, two of them are running away and one is sacrificed. It is very hard to win points from kills for me at this point, unlike when I was Plat.

Do you think it's expected player variance, am I exaggerating?