If everybody makes the same amount then all you’ve done is inflate the currency. Money is used to control access to finite resources, with the goal to get more tokens than the other person. If you give everybody X tokens per month, then in aggregate things will cost X tokens more.
No inflation required. People buy things from whoever owns the production, and the producers pay high taxes to fund the UBI. No net money creation required.
Then you've created a net deficit. You can't ignore algebra and pay more than it costs to make something and put it on the shelves. Without those paying people to put it on the shelves making more than it costs to pay those people there's no incentive. This is a pipe dream without causing inflation and doing nothing in aggregate.
