IMO that problem can be traced back to issues like:
1. The Permanent Apportionment Act of 1929 which prevented adding more Representatives as population grew.
2. The game-theoretic outcomes of continuing to use plurality/first-past-the-post voting.
3. How most officeholders end up spending most of their time raising money for re-election rather than the job itself.
With a magic wand I’d massively increase both the house and senate, publicly fund elections, and switch to 3 member mixed districts to increase the chances every citizen of a district has someone they feel reasonably represents their major views.
I’m not saying it’s worse than what we have now, I’m actually more curious how the people who would like to see that reform would want it to look in practice so I can know whether I could support it and how I’d argue for it.
When I’ve pictured this it’s with member counts in the low to mid thousands, not tens of thousands.
Floor debates are already mainly performative, with little bearing on changes to bills. All the real work happens in committee and by the Speaker’s office. I’d think about embracing this with more different caucuses of various members who come together on specific issues and bring versions of bills and amendments for committees to adopt or reject, maybe even a few levels of committees to build consensus slowly so the final floor vote is more formality than debate.