Your theory about companies raising prices to offset UBI is actually undercut by historical and present evidence.
There was a time when the United States had welfare. The United States still has food stamps. But nobody is seriously pretending that these things did or do drive up grocery prices.
Similarly, over time various states have raised minimum wage, and if your argument were accurate, then the prices in those states would have immediately risen to match minimum wage, but they didn't.
In other words, you're repeating a conservative talking point that has been repeatedly debunked by reality. I think you could try to improve your argument by arguing that inflation happens across the board, to everything, and therefore it would also happen to UBI. But what we've actually seen is that's not true.