I think there are 3 factions in a world where AI took out most jobs (with UBI of course):
#1 There will always be jobs requiring humans - jobs that require human interaction. The supply will be much smaller, but so will be the demand.
#2 By the time AI replaces all jobs, we will most likely have a very realistic VR with multiplayer capabilities. I think that many people will live adventures in such world and spend most of their waking hours in it. Metaverse sucks but it's only because it's so artificial. If you could have tech that could integrate with your senses directly, giving experiences on par with the sharpest lucid dream... that's going to be much different and for better or worse, a lot of people will get sucked into it. Of course, it's going suck - life is about yin-yang, endless pleasure is not good. People who will end up spending the majority of their time in such VR will not be unlike drug addicts, unless they will also be doing activities that require mental & "physical" engagement (I think one of the coolest thing that could arise out of it are new sports that would not be possible in the real world), however, that yin-yang balance would be hard to achieve when there's no evolutionary pressure combined with overabundance of simple pleasure that's just available all the time.
#3 Walking the path to mastery in some pursuit - i.e. artistic, athletic, a craft. There's pure joy in just getting better at something and enjoying every day of practice and most importantly - feeling challenged which is a primal need. It may be competitive as heck to get some recognition or play in the big leagues (which would be more like #1), but that would be just a bonus from that perspective.
If AI leaves us nothing to do, then #3 will always be available. AI will not take away our own engagement but engagement requires effort and so, I would bet that a significant majority will overindulge in #2 to their unconscious doom - I guess it will still be a pretty cool experience though and it's not like those people will not have a choice to get out.