I have H1B and my stamping expired in Feb '2020 but my renewed I-797 is valid till Dec '2022. I’m planning to visit India in June (5 months before my visa expires).
My question here is, instead of applying for visa extension here in US (which I can in June) to get the I-797 extended for 3 more years, can I travel to India and use the In person Visa Interview waiver and apply for 3 years extension through Dropbox option?
Yes but you still need a I-797 extension of status approval from USCIS to get visa stamped. Visa is just a travel document and not a work authorization. Work authorization/I-94 is either issued by USCIS attached to the I-797 approval notice (I-797A) if the extension of status is done in the US or be approved with consular processing (I-797B) in which case USCIS will not issue I-94 with the I-797 but you will need to go for visa stamping and when you enter back to the US, the CBP will issue the I-94 to match the I-797 expiry. I-94 governs your legal status in the US.
Anyways you should be discussing your travel plan with the employer’s immigration lawyer and they should be able to guide you .