The word “fairly” is doing a lot of work there. There has been a lot of success on one side to tilt things with redistricting and voter suppression since the 80s.
Redistricting and voter suppression are definitely a problem. If they were both done in a way that was technically legal though, we can't be too angry about it before we change the laws that allowed it in the first place.
Fairness in the context of an election only means that it was done in accordance to the existing laws. Maybe equal access to voting needs to be on that list too, but I'd expect that to be covered by voting laws.
The purpose of the laws should be to ensure fairness. Fairness is not defined by the law. Unless you consider it was fair for women not to be able to vote, when that was the law.
There have been many attempts to fix districting laws, but of course those changes have to be approved by representatives elected under the previous laws.
It has been difficult to challenge these in court because it’s hard to argue whether a districting is “fair”. There has been a little progress on challenging some districting based on a statistical argument that shows the one-party advantage resulting from the particular districting is extremely unlikely to be the result of chance.
