When it comes to holding the majority in the House, it depends on the election cycle. In certain Midwest swing states, the Republicans might have an advantage in some years.
In any case, the future of the House majority is dependent on how each state’s congressional races play out. Every state has a different number of congressional races and those races can often be competitive. There is no guarantee that a party will maintain the majority, especially with the growing importance of independent and third-party candidates in certain states and a competitive presidential race.