Didn't watch. But here's the thing: we have point-buy, and we have random roll.
If you have point-buy, players will naturally try to get as much as they can for the points they have. They'll optimise. This is hard-wired into humans, that's why if 1 thing in the store is $100 and 2 things are $150, you get 2 - even though you actually only needed 1. That's why after the lockdowns took away commuting and gave my wife 2 hours a day to do things other than get dressed for work and walk to the train station, wait for the train and take the train to work, she's not keen to go back - she has 2 more hours to spend, and wants to spend them as best she can - the other 14 waking hours are already accounted for in work, kids, and so on.
Humans are creatures who want to best spend limited resources, like time, money and character points for "builds". Given limited spending, we look to optimise that spending, get as much as we can for it. This will always happen, and many game writer's and game master's hours have been wasted trying to stop players doing it.
But if they use random roll, that sidesteps the whole problem - assuming you consider it a problem. There's nothing to optimise during character generation. "Roll 3d6 down the line, choose the class you qualify for. Write it up."
Now, depending on the game system, there may be some optimisation later on with feats and skills as prerequisites for other feats and skills, and so on. So again, choose a different system, and avoid the entire problem.
The last point is that whatever system you use, you as game master have to emphasise to players that they're in a party of adventurers - they work together. The individual character doesn't have to be optimised for any and all situations, they just have to be good at 1 or 2 things - it's okay if they're crap at other things, because someone else in the party will be good at it. This is true of real world "adventurers who wok in a party" - soldiers. You don't expect the medic to be a crack shot, and you don't expect the machinegunner to be much of a medic.
This is a mindset thing, and unfortunately players' minds have been polluted by generations of computer games with a solo character who, by virtue of being on their own, simply has to be good at everything, and star vehicle movies with Mary Sue characters, like Tom Cruise's guy in the Mission Impossible movies. So the game master has to emphasise this to players, and construct scenarios which reward individual specialisation backed up by teamwork.
So: random roll, and teamwork. And then optimisation becomes impossible, irrelevant, and not desirable.