You just said "then". Where is the argument?
So if I earn $500 now, and buy 500 lollipops at $1 each.
If everyone gets $1000 as UBI, then those 500 lollipops will cost ... $1001 each and $501000 in total?
Isn't that absurd?
That is what the sentence "everything will cost $1000 extra" means, and the only way "raising the value of zero" makes mathematical sense.
What is probably meant here -- that the sum of what you buy will be $1000 more in total -- is accurarely captured by the term "inflation" in the OP.
But then the statement "raise value of zero" does not make sense.