There are seven states with only ONE House of representative: Alaska, Delaware, Montana, North Dakota, South Dakota, Vermont, and Wyoming.
The reason for the above is that there are so little population ( less than 650,000 )in the whole state.
These 7 states each have TWO senators.
The reason for this is this is how the country was formed giving 2 senators to each state in the constitution. These 14 senators are always Republican and see their weight on 100 seat Senate.
so two reasons why US cannot reflect the wishes of the majority of the voters.
1/ fourteen senators from 7 states ( with a population less than 650,000) elect the same Republican senators for decades ( think about their influence on judicial judge selection and every other decision senate make)
2/ as you mentioned, state-level gerrymandered ( in bigger population states) electing more House reps of Republicans even though their vote share is less than 50%
https://ballotpedia.org/United_States_House_of_Representativ...
https://www.vox.com/2014/8/5/17991950/how-gerrymandering-wor...