Heh, wrist locks suck so much.
Outside that wrist lock though, I bet you could have stacked her and got your hands behind her head enough to can-open her at the same time; 225lb you + can-opener + hard stack on 125lb her = no more triangle in like 95% of cases lol.
Don't get me wrong, it's douchey as hell, as we both know, and probably not something you'd ever do... but that's not how an incoming white belt thinks.
The incoming white belt stacks her, probably doesn't even know the can opener unless he saw it online, and just puts his fist into her throat while pressing down as hard as he can while also crushing her.
Sure, she might put him to sleep... or he might slip and drop an elbow on her at the same time. Or slam her. Or do a twist escape full force and torque her knee until it gives out and he escapes.
And I got the vibe that the op meant even bigger than you or I when she said "giant" whitebelts.
I'm not trying to say that it would or wouldn't go any particular way; I mean I just don't know, in any individual case there are so many variables. I suspect though, that across all of BJJ, using BJJ rules, super-tough man killing women are fairly rare. I would also suggest that this effect is amplified in no-gi.
As an annecdote, and I realize how unuseful that is, I was asked to go as hard as I could against a 140lb, 5'6", female blue belt, 4 stripe. She is undefeated in 3 cage fights and hasn't been submitted in competition in years and we were having this very same discussion.
She asked me, as a close friend, to give it to her straight and give it my 100%. We did straight BJJ and then briefly mma. The details don't matter, but it was shocking how easily and absolutely I beat her. She was appalled, honestly. She thought it would be way more competitive than it was. I literally can grab her wrist, twist it, and submit her... and that doesn't even get into how ugly it gets if I get on top.
Now I freely admit that I'm not a new white belt and that I am more experienced than her... but she would have had to be way better to not have gotten wrecked the way she did... and she's one of the toughest women I know.
Afterwards we wondered if the skill difference made up most of ass kicking. We have a blue belt who is hyper competitive and very skilled...but nowhere near purple belt level (she'll probably get promoted inside a year). When he turns it on, the result is the same. More competitive sure, but just as inexorable. The only (rare) submissions she can hit on him when he's going 100% are leglocks, and it won't be long before he learns enough to shut that down too.
Again, I'm not trying to impugn anyone's skills or say any particular person could or could not beat me or another guy or whatever... I'm just suggesting that, on the whole, men are significantly stronger than women, that it absolutely comes into play in our sport if we let it, and that the difference is more than many men really realize.
I try really hard to take it at face value if a woman says a guy is using too much strength, even if the guy figures he wasn't... and I especially try to keep an eye on things if it's a new(er) white belt and a senior female, because they really do seem so much more invested in winning. It's like they realize it's their only chance to actually tap someone that day, and they lose sight of the fact that it's a woman who weighs 50 - 150 pounds less than them.