Since we know that it isn’t constant with time, how can we be sure that it is constant with space? This might be a reason the variability in our measurements which seem to disagree.
Put another way, why couldn’t the universe expand in one direction preferentially compared to another?
So, this just popped. https://www.livescience.com/space/cosmology/james-webb-telescope-confirms-there-is-something-seriously-wrong-with-our-understanding-of-the-universe which may be relevant. Haven’t read it yet.