Govt doesn't interfere in choice of procurement outside the list of options the forces provide. For example, if the IN wants an SSN, the govt's not gonna go out and buy something the IN doesn't want just 'cause it's an SSN. So even at the highest levels, the govt goes out and buys only what the forces want. In this case, the IAF is voicing out their opinion that they do not care much about a 5th gen import. And not 5th gen, but a 5th gen import. Huge difference.
Plus, not even a stopgap, they want something they can change over the long term, so a license production deal. That's the main point.
Btw, Modi-Trump, nah, Modi never said anything about the F-35. Only Trump acting like a salesman for the F-35. That's not relevant to pretty much anything the IAF is doing. Trump's push for the F-35 means it's just the same low-hanging fruit the IAF has access to as any other available option, like the MRFA competitors. Trump is just pompous enough to sound like he's doing India a great favor by allowing India the opportunity to beg for it instead of participating in MRFA.
As ACM Singh said, any import will be via Make in India.
Plus, even at the highest levels, like the PMO, there is no interest in just importing a new jet like we did the 36 Rafales.