Yes, 6E was always a viable option, but not via the codeshare agreement with QF to operate the 6E leg as a QF number.
My understanding is, some 'N' years ago, QF had a codeshare agreement with 6E to operate domestic IND routes on a QF number as part of international itinerary. So SYD-BLR-MAA or MEL-DEL-MAA would be 2 QF numbers, rather than 1 QF and 1 6E number.
Fast forward a couple of years, 6E was then given the authority to fly international into SIN and QF then got another agreement (or extended the existing codeshare agreement) for 6E to operate as a QF codeshare from SIN to cities in IND. So there is a 6E SIN-DEL/BOM/CJB, from memory. However, there is still no SIN-MAA/HYD/CCU/CGK as a QF codeshare.
Happy to be corrected.
Edit: Side Note: late last year MH got into an agreement with 6E to operate some domestic IND routes as a MH codeshare. Notably, there is AMD-KUL-SYD, that operates as a MH number all the way, with AMD-KUL in a 6E aircraft.