A simple change would be to give an option on the Roth 401k that says “treat this account like a Roth IRA for withdrawals”. When a user selects this option they acknowledge that they would need to convert to a Roth IRA in real life.

yes – option within the Roth 401(k) settings to indicate when (age, date, milestone) this account rolls into a Roth IRA.

+1 - this scenario would be useful to me as well because my employer offers both traditional 401k and Roth 401k contribution options and I do contribute to both. When I leave employment I plan to roll that 401k into their respective IRAs and unlock the free withdrawal of contributed amounts to bridge the gap between early retirement and qualified withdrawal age. Today in ProjectionLab I have to use two accounts to represent this single 401k. On the rollover, I I would ideally like this function to take over the Roth 401k contribution amounts as well so that these show up as penalty-free withdrawals during the gap years.

I have a traditional 401k, but would like the option to automatically rollover on my retirement year into IRA, which I then have set up for Roth conversions.