As we understood the matchmaking is based only on the number of trophies, this means that even though you can stand at 2000 trophies at BH3 you will always find BH5 and BH4 only.
How can you not be so disadvantaged? Use a special BH4 layout that can also repel attacks from BH5 with War Machine.
In following video, it will also be demonstrated how it can perfectly break down BH5 enemy attacks: the structure of the village is pyramidal. The south side is open and allows you to attract more “naive” players, in fact what may seem easy will become infernal.
The south part is well-covered by defensive buildings and well equipped with traps such as spring trap or giant mine. Usually enemies will use ground troops as it may seem the least demanding route.