Your solution eliminates accountability to donors, but it also eliminates accountability to voters.

Both houses essentially have this. It is called a voice vote.

How will voters know whether their reps are voting for the right things though

They wouldn't! That's the downside. Or maybe not a downside -- there could be an even stronger incentive for politicians to get stuff done. Since voters would have to make their decisions based entirely actual results, and not an individual politician's voting record, the politicians might have a stronger incentive to build coalitions and influence other politicians' votes.

My half-baked point is that the harm of voters NOT having access to this information is less than the harm of lobbyists and major donors having access to it.

That doesn’t really work though, people vote for their rep, not some amorphous party blob.

On the other hand, it gives pols plausible deniability that they aren’t getting bought out.

I should point out that places like Germany do vote for the party, not the person for positions like Parliament. In each region the parties submit slates of people they would put into the positions if they got all of the votes, and then once people vote they get a proportionate number of their slate into actual offices. There are lots of details here, but it is a system that works.

They vote for both party and person in MMP. Voters submit both a party list preference and a candidate preference.

Any differential privacy experts care to weigh in? Is there a differential privacy method that can introduce a specific amount of noise in voting results in order to not fully hide nor fully reveal specific representative voting records?

What they say and how they behave. I really don't believe there are a relevant number of people who can consistently say one thing and vote a completely different thing for years on end.

Maybe I'm naive, though. I really do think nearly everyone in congress does want to make the world a better place, they're just lost/confused about how to go about that, often getting caught up in the game of staying in congress rather than using their time there for good.

It's actually how congress worked before the "sunshine" act of 1971 which made voting records public.

The vast majority of people don't actually go and look up their senator's/congressperson's voting records, where as lobbyists do. So I think the voter disclosure argument is overblown; I don't think that voters actually need to know the exact voting records of their congressperson. I think voting should be selecting people based on character and rhetoric and then letting those people act as representatives.

It would be less democratic, but more functional (and more akin to what the founders imagined anyway).

I'd prefer the regular public voting and a secret non-binding vote. You'd get a lot of information out of the secret vote telling you what representatives really thought. Especially if it were a landslide in the secret ballot and down party lines in the public one. You can think of plenty of examples of past issues that would have gone that way.

In firing squads, one rifle holds a blank to preserve the possibility in the hearts of the shooters that theirs was not the shot that killed.

I imagine blind voting would also serve to assuage the worries of legislators. If only we knew what each worried about.

Firing squad members don’t usually fire more than one bullet, and it’s very obvious if your case was blank or not.

Not sure quite what you mean. It sounds like list voting, is that it?

I don't know how exactly it would work, I just mean a system where only the final vote tallies are made public -- not WHO voted for what.