No, that’s not true. Otherwise, you wouldn’t have information like this, the breakdown of votes by members on the 1964 civil rights act.
https://www.govtrack.us/congress/votes/88-1964/h182
It may be that prior to 1970 or so the number of bills (or the number of bills salient to major donors, or whatever) passed by voice vote rather than recorded vote was higher, that’s a harder claim to assess. But it is certainly not the case that Congressional votes either (1) were ubiversally nonrecorded prior to sometime around 1979, or (2) cannot be by voice vote today.
Recently, the House Republicans publicly voted to back Marjorie Taylor Greene (strong Trump supporter) but also had a secret ballot to back Liz Cheney (Trump critic, voted to impeach, #3 in House Republican hierarchy).
It seemed obvious that if the second vote was public that Liz Cheney probably would have been censured and lost her position.
We insist on secret ballots for individual voters so they can't sell their votes, but for our legislators whose individual votes are far more consequential, we've given up on it.
In exchange, we get to see how they voted and "hold them accountable." But we can't do that nearly so effectively as corporate donors. Most of us don't look at voting records at all; our information mostly comes from attack ads taking votes out of context.