Most warplate topped out at around 60-70 lbs distributed all along their body. That's nothing like repeatedly firing a longbow using your arms. Now, tourney plate could get a bit heavier (100 lbs is the absolutely heaviest I've seen) than that, but that's tourney plate, you aren't really expected to even move with that on you. But it can take a lance to the face like no ones business.
Mate, I am an active HEMA participant. I know damn well how much strength is required to actually swing a sword around. Not that much, surprisingly. Swords are really light, longswords were usually around 2.5-3.5 lbs (as were most maces and axes). Now the gargantuan zweihanders were admittedly quite a bit bigger, but even they were about 8 lbs (a bit heavier than the Dane Axe), usually a little less. What is true, is that pikes and other polearms were quite a bit heavier, usually around 10-15 lbs, and importantly, weren't really used by the knightly classes all too much. Those were soldiers weapons, meant to be used in a formation. You weren't really supposed to swing those around consistently, the pike (I think you mean spear crossed with an axe, you said spear crossed with a pike) you just hold in front of you, or set it with your foot, while the halberd you hold out in front of you and occasionally make a scrapping motion with. Now, the pole-axe was far more nimble, but they topped out at around 8 lbs as well. Strength really isn't as important as most people think. What is important is endurance. So important, seriously, your shoulder will feel like it's going to fall off because you get so tired.
While firing a 100 lb warbow requires strength, pure brute strength. Especially if you're actually pulling the thing back all the way (most people don't go back far enough, admittedly, they're not using period appropriately long arrows) much less shooting the thing repeatedly for an entire battle. It simply requires more arm and shoulder muscle power than melee weapons do, even when including armor. And we can verify this, in period texts we know the English had a problem with longbowmen washing out because they grew too weak to fire their weapons consistently. This really didn't happen with the normal soldiers, and many of the longbowmen then just got downgraded to a pikeman.
Now we do have knightly bows on record. The ones I've seen topped out with a draw-weight of 60 lbs. They did not use English longbows on horseback. Smaller, easier bows to aim while moving, just trying to get the full draw out of a longbow on horseback would be perplexing.
Now, we do have records of knights who were also longbowmen. English, obviously, who are mentioned as being in charge of various units of longbowmen in battle. They were not riding into battle on horseback with their melee weapons and armor. And that makes sense, knight is a title, not a military position (though the two do most often go hand in hand).
I would also note that by the rise of full-plate, axes (that weren't pole-axes or halberds) fell out of favor because they really couldn't break the armor anymore. They worked decently well against mail armor, which is why the Dane Axe was so popular leading up to plate. But if you read the treatises, you see that weapons like the pole-axe and halberd had the axe sections not really to deal with the guys wearing the full-plate, but everyone else.
So, ignoring magic, because that just makes everything wonky and nonsensical. Strongest champions should still be Ashe and Varus. I'll give you Quinn probably isn't up there in strength, after watching her animations it looks like she isn't reloading her crossbow. Which instead seems to have some sort of magazine, I guess like a cross between a Zhuge crossbow and a modern rifle. No idea how they'd get that to work, but, I'm not going down that line of thinking.
maybe with her full rework.
those thighs gotta be huge for all her kicking 
similar to riven - she's strong, but her gloves are what puts her over the top - someone who works out regularly and is very well toned
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should be more buff, not like Illaoi but like Sejuani