Tbf UBI-lite during COVID was paired with 2 things:

1) massive handouts to business owners through forgiven “loans.” Predictably this had massive fraud, some of which was prosecuted but not much.

2) massively constrained supply chains which caused higher prices.

I suspect 2 at least would have caused inflation regardless of the stimulus checks.

It’s unclear to what extent UBI causes persistent inflation. Proponents claim the backdrop of a minimal income will enable more risky innovative projects which could increase GDP growth enough to counteract some level of increased inflation.