Not necessarily. It's straightforward to make it revenue neutral.

You make it revenue neutral for the average tacpayer. If you want UBI to be $1000/month, you increase the average tax by $1000. The average taxpayer still benefit because even though they don't get more money, they have a safety net.

People making less than average get more UBI than the tax increase, and those making more pay more.

Most people get more money because the median income us a lot lower than the average.

If the only money is UBI money then things start to get weird. If UBI coexists with regular income in moderation then it doesn't change much. Consider that about 1/3 Americans receive some form of government assistance. There's already a kind of fallback UBI distributed across SNAP + Medicare + Medicaid + Unemployment + Social Security + etc, and no one on those programs is clamoring for them to be shut down so that lentils become cheaper. Giving money to everyone does increase inflation (though you can play with the tax rate to offset that), but the important effect is it transfers purchasing power to net recipients. Basically: the economy wide money supply would at worst go up by a modest factor, the income of the poorest goes up by an absolute amount (or a massive factor if you want to view it that way), which is a huge benefit to them.

"Solve the problem" probably not, but trigger inflation, probably not, since the amount is so low, it will have very little impact on the behavior of the richest, but it would have a massive impact on the behavior of the poorest, and their purchase habits generally don't impact inflation as much.

UBI is just a band-aid on not taxing the rich, though.

Not everything, only stuff that are suddenly in higher demand that can't increase supply. If you take food as an example i don't imagine demand would increase? And if it did we could probably just produce more? And also it's not like everyone will have unlimited money, so you'll still have to prioritize and luckily we don't all have the same priorities. I'm pretty sure the idea is to fund this by taxing production and not by printing money, so inflation shouldn't be a problem.

Yes, it does cause huge inflation, but that's not even the biggest problem with it. That would be: people do not really like to share fruits of their labor with strangers, so UBI would significantly undermine the motivation to do anything other than bare minimum.

UBI is not possible until robots and AI take over most jobs (but then we risk that one day the AI decides to just get rid of "those useless humans")