There’s a spectrum of ways to reform the House using proportional representation. Two key factors are how many representatives a multi-member district would have and how winners of House seats would be proportionally allocated.
In 2021, Rep. Don Beyer of Virginia led a group of other House Democrats in reintroducing a proposal that’s been floating around Congress since 2017. The Fair Representation Act would require states to use ranked choice voting for House races. It calls for states with six or more representatives to create districts with three to five members each, and states with fewer than six representatives to elect all of them as at-large members of one statewide district.
And it’s not just the salary for the representatives but they all also have a state-paid office and staff - so yeah…
There have recently been reforms to make the districts bigger to get less direct representation in total resulting in a smaller size overall.
I’d expect that especially with a 2-party system it’s not as bad as you calculated though since the worst problem here is that a local party from Bavaria is winning almost all the direct representation spots there but gets way less votes in total in Germany which results to every other party sending way more people than they would need