generally the constitutional prerogative of the states- I'm not sure what the Federal government can do to encourage it.
But if you don't like Tlaib or Omar, they are a function of gerrymandering- representative of districts that were gerrymandered to lock as many potential D votes away from the safe R ones as possible. True of Gym Jordan, etc. as well.
Not that those might not be strongly D or R leaning districts with any reasonable geographic composition, but less likely for the election to basically be a matter of choosing the most extreme person in the dominant primary.
You can't get around that in some cases- not much way to change ones like AOC's Brooklyn district or SD ad hoc.
But you can be assured that if people in WI or MI happen to finally get tired of the R gerrymandered lock on their states and take the keys away they'll get the religion within a cycle or two.