If "we" means everyone, yes. But the reality is there is a sufficient number of people willing to work more to earn more, and therefore they will raise prices of everything which destroys your purchasing power.
Your purchasing power is defined in a competitive equilibrium with your peers.
If you're assuming you can band everyone together to all decide to work fewer hours for the same pay, fine, but you just invented a union, not an improvement to UBI.
There are people working 80-hour weeks now. I don't think "some people want as much money as possible" is the basis of how we should think of labour. Plenty of middle-class workers will be happy to work fewer hours if they can maintain their current lifestyles.
> If you're assuming you can band everyone together to all decide to work fewer hours for the same pay, fine, but you just invented a union, not an improvement to UBI.
Why should this come solely via unions? I elect people to represent me, and I want those people to tax AI/tech companies and their beneficiaries, and return some of the wealth they've generated to the people it's been extracted from. The entire point of UBI is that it's universal, including in industries poorer and more vulnerable workers who can't self-organise work in.