It's rather secondary to the real objection to UBI: paying for it.
I'm saying BOTH that it's good for people AND that it's affordable are still in dispute and that the claims are clearly not obvious.
The arguments - with varying degreees of plausibility - are all of the form 'long term welfare dependency is unhealthy for society' not, 'welfare recipients would be happier if their welfare income was lower'.
And that's not conflicting with reporting less financial stress during an intervention. The self-reported consequences from eating some candy are very different from the consequences of using candy as a primary diet for long periods of time.
If you won $1bn in the lottery, you'd be quite rich and, in so far that money can make you happy, probably also quite happy. If literally everybody won the lottery at the same time and got $1bn, you'd be back where you were before winning the lottery, as your $1bn wouldn't have the same relative value. Sure, you have a billion, but bread now costs $100k and your rent is $100m.
I happen to believe they are but this study doesn't establish that; and we are missing a golden opportunity to do some real UBI studies with the billions in aid that are suddenly sloshing around.
Checkout the auto complete in DDG or Google for "welfare causes ...". Look at the arguments in the results.
We can't even have the discussion that you say is "the issue" because society is still stuck at the part you claim is obvious.