When we bought the S400 we limited our Next Generation Stealth Fighter Options. If you see where the F16s are being offered or sold , are states where offering F35 is either economically or politically not possible. Otherwise LM , wherever it is competing in a fighter jet competition, the offer is F35. And with S400 we have closed that door for us. Our only options are a derivative of Su57 or AMCA. That's why I believe that AMCA will happen. It might not be enough to replace Flankers, but it is only option we have.
On TEDBF, it's directly linked with if IN convinces the parties for 3rd AC. Because for the interim I see IN making do with the 40+ Mig29K for Vicky and Vikrant. And it's not like the capital investment in Mig29K is small, so if anyone says that IN will give up them before 30+ years , it's not worth believing. Only way TEDBF can be realised is if IN has 3rd AC approved.