UBI would be a good bandaid for alleviating the problems of the working class. But in capitalist countries it would only be a means to an end because it does not change the political economy in any meaningful. The bourgeoisie still control the means of production so UBI would just be a concession that they can take away if they want.
Many UBI opponents SLAM it for reasons like it might cause inflation. I don’t know enough about the economy to know if this is true or if it is whether it can be reigned in via measures such as price control. These people to me always reek of being “rampant inequality enjoyers” that hide their viciousness under the veil of fiscal responsibility.