Here's a potential 2020 map:
IA-01 and IA-02 are tossups pretty much, while IA-03 and IA-04 are safe D and R respectively.
So in terms of net effect it would just be switching the Safe D district from 2 to 3. I guess that's fine. I think Loebsack and Finkenauer would be relatively safe for a while in this map. They both seem to be popular and are pretty good fits for their districts.
Iowa is interesting because it seems to be the only place where the "population tilting" of the Midwest (east is flat or losing population, west is flat or gaining population) is working in reverse. Western Iowa is emptying out fast, Eastern Iowa is doing just fine.
At least based on Census estimates, 3 is still too big, maybe drop Jasper. As for population growth in the state it's not so much regional as it is Metro Des Moines and Metro Cedar Rapids-Iowa City growing while rural Iowa declines and smaller cities are relatively flat.
FWIW, that map was done on 2018 estimates--it'll obviously require revising once this census is actually done but it should be pretty close.
