It appears you may have misunderstood.
First, the first 12 months of practice is the last half of 2021 and first half of 2022, so I maxed out retirement contributions for all accounts twice during those 12 months.
The 65K was cash, not tax exempt. Knowing I was returning to fellowship in summer of 2022, we just saved a bunch of cash to supplement income during fellowship instead of moonlighting, and as a "car fund" to fix or replace our cars if they give up the ghost, as they're 17 and 20 yrs old.
104K in Roth:
Roth 403b: 2021 - $19,500, 2022 - $20,500 => $40K
Roth 457b: 2021 - $19,500, 2022 - $20,500 => $40K
My Backdoor Roth IRA: 2021 - $6,000, 2022 - $6,000 => $12K
Wife Backdoor Roth IRA: 2021 - $6,000, 2022 - $6,000 => $12K
So in that 12 months, 80K into Roth 403b and Roth 457b and 24k into Backdoor Roth IRAs. it was a total of $104K. All of this was POST-tax (hence, Roth).
The other $52K in PRE-tax, tax-protected accounts is from mandatory employee 5% contribution and employer 10% contribution. Salary was $343K for the first 9 months, but bumped up to $357K for the last 3 months after board certification.
343 * 0.75(9months) * 0.15 = $38,587
357* 0.25 * 0.15 = $13,387
Those added together equal just shy of $52K
Make sense?