Just finished "Bullshit Jobs" and it ends with advocating for a UBI, explicitly as a plausible first step towards fixing/dismantling capitalism.
Its a pretty solid argument, as long as you put the caveats of the goal to be to expand the benefits of society universally, not to consolidate the welfare state and reduce cost.
There are a lot of issues and technical details that one can imagine, and ultimately if the goal is to liberate all humans and save the world from capitalism, further steps would have to be taken. But a UBI does seem like a reasonable first step.
Though I guess the only would world the capitalist class would ever let a UBI happen is the world where we force them to, since even the $2000 one time payment basically is never going to happen.
So UBI as a advocating tool or a rhetorical device, but I don't think it should be a goal in of itself. A UBI is the compromise position and leaves the Capital class in place. Something closer to Universal Equal Payments (working title) should be the goal.
I used to be more against UBI but I am less so these days since it is an easy and practical solution to quickly implement and lessen inequality. I would just be wary of those who only focus on UBI, since as you say it still doesn't do anything about who owns the means of production and thus who controls the real power in society.
In a capitalist society, the Bourgoise will give the worker just enough to not start a revolution. That's why we got the 40h/week and then nothing changed anymore. Therefore, I have two hearts beating in my chest. One, that wants revolution and one that doesn't want to see people dying. UBI would change our society but the biggest winners will not be the workers but the landlors. If you have a UBI without any further regulations you would end up with living spaces that start at the UBI. I'm afraid UBI would strenghten capitalism instead of weakening it. I'm almost sure it wouldn't be a stepping stone to overcoming capitalism. However, it would make capitalism more liveable and maybe that is a good thing. I dont know.