>so all goods and services that require said "dirty job" in the supply chain will go up in price. This eventually negates the UBI benefits, because the level of UBI no longer can sustain purchases of all the goods and services that it originally could due to the increases in prices.

Isn't this the same argument that's used to argue against increasing the minimum wage? "if you increased the minimum wage, then the costs will go up for those businesses hiring minimum wage workers, making the goods more expensive for those workers, and canceling everything out!". But empirical evidence has shown this has not been the case[1]. Because of this, I'm wary of any hand-wavy arguments like these that just mention some effects without attempting to quantify the magnitude of those effects.

[1] random result: https://commons.wikimedia.org/wiki/File:CBO_Projected_Effect...