Roth 401k = you pay taxes now. This is beneficial when you *know* your tax rates will be higher in retirement when you will tap the money.
Do you *know* this? If not, why not do normal 401k + regular Roth (regular Roth X 2 if you are married)? There are income restriction for regular Roth, but that can be worked around with "backdoor Roth" - google it here and in Bogleheads.
With global move between US and another country, some tax games are often possible. I have worked abroad and it worked to my tax advantage - greatly. On 5 minute google - I dug up the RNOR status in India (
https://economictimes.indiatimes.com/nri/nri-tax/all-about-resident-but-not-ordinary-resident-and-why-this-special-status-is-accorded/articleshow/18275734.cms). Perhaps you engineer a situation where IRS considers you non-resident and Indian Govt considers you RNOR - and withdraw money tax free?? Who knows? May be worth a visit to tax law experts in both countries!!
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Based on Bogleheads international investing forum - investment options seem quite bad in India. High expense ratio, and very difficult to invest internationally. So I'd probably leave some money invested in the US as a hedge even if you do return.
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Why do you want to return? There are significant financial costs to returning. You pay into Social Security and Medicare, but get nothing if you "return" before becoming a US citizen. As a visa holder - you have to have significant income and be making significant contributions to these. This could be a lot of money for you to leave on the plate.