I once took two IQ tests on the same day.
One: 133
The other: 167, which is stupid high. Due to peculiarities of the test for me, it was inaccurate.
Tests vary. But I can assure you that the consensus of psychometricians is that IQ, properly measured, cannot be significantly raised after early childhood, if then.
We do know a bunch of ways, however, to bring IQ down.
IQ’s can vary upwards of 15 points from your personal mean average on any given day. There are many factors that are behind this.
From what I have read on IQ’s, it can be changed by somebody who is willing to work hard at it and keep working hard at it, though there are probably limits on how much more intelligent somebody can become from what they were born with.
IQ will be replicated by AI but not so much with creativity, of which IQ is a component.