I've been curious about questions like this and have tried to read some things on my own. I have a few thoughts that may well have errors or misunderstandings.

1. Of all the various schools of economics post-keynesian economics (PKE) made the most sense to me. "Monetary Economics" by Godley and Lavoie is a good reference. A few claims: the money supply inflates and contracts based on the credible demand for loans and the bank money multiplier does not exist in almost all modern economies for the past 20 years. https://www.exploring-economics.org/en/orientation/post-keyn...

2. In section 10.7.3 of Monetary Economics they do an experiment where government expenditures have a sudden and permanent increase (in this setup the government borrows money for the expenditures instead of simply printing money). The experiment uses a simulator with watertight accounting and models various interdependencies between consumer behavior, consumption, banks, interest rates, etc. My reading of the results is that in the steady state inflation is higher, households have more disposable income (good) but their assets depreciate at a faster rate due to increased inflation (bad). The steady state output, consumption and income are all higher for households. Interestingly the debt to GDP ratio initially increases and then comes back down when inflation increases (inflation is helpful for borrowers).

3. I am not familiar enough with this book as I should be but I believe there's some assumption here that new deficit spending actually leads to new economic output. Meaning the well of new investment opportunities and capacity of existing businesses has not been tapped out. It seems like as long as this assumption holds this simulation is saying that increasing the deficit will in the steady state lead to increased inflation and a loss of savings from depreciated assets in exchange for more consumption and output.

I'm possibly more interested in the case where the government uses deficit spending over a limited period of time to combat a recession or high unemployment.

4. This may be straying from PKE but a common rules is that inflation is positive if the money supply increases faster than GDP increases (you've produced more currency than goods). I believe this assumes that human behavior of consumption is relatively stable (the velocity of money and the propensity to consume/save do not change). Following my own thinking, if the government uses deficit spending to send $100M in covid checks, and there is some slack in the economy where businesses are ready to produce more goods and services at roughly the same price levels, then this could reasonably lead to an additional $150M worth of economic output (someone spends $70 of their covid check, the recipient turns around and spends $50, etc). In this example we have increased the money supply by $100M and increased output (GDP) by $150M. Does this cause inflation or deflation? Have we increased the money supply faster than GDP? That depends on the existing ratio of money supply relative to GDP. And to get that ratio we have to decide which money supply (M1, M2, M3, M4) or weighted average we are considering.

5. The point of the above is that I believe there is a case where government spending could unlock an economy that is not at full labor and production capacity and actually cause deflation (more goods are produced relative to the increased money supply than the existing GDP/MoneySupply ratio). If in the other extreme no businesses has any spare capacity to produce more and there are no investment opportunities than nothing is added to the GDP and the money supply is increased so there must be inflation.

To answer your question is: given a leading simulation with reasonable assumptions and an economy that can increase production a UBI program would cause the steady state of inflation to be higher. Over a shorter horizon given my amateurish assumptions the answer is maybe.