First of all, indigenous doesn't mean developing it alone!
Secondly, different partners can be used in different fields for different advantages!
Brazil / Embraer have good experience in the aero field, is an emerging country, most likely will buy Rafale as well and will have a similar requirement for CATOBAR carrier fighters.
=> That means, they are the perfect co-development partner to jointly fund and order AMCA with similar requirements and in numbers that will reduce the operating costs too!
Dassault with the Rafale licence production and the offsets they have to return to Indian industry, they are the perfect industrial partner for any future indigenous development. In this case, there is even hardly any better since Rafale was developed at first for navy and as a CATOBAR fighter.
=> So be it for the development in general, or for the navalising of the fighter, they are an obvious choice!
Engine and radar (preferably Snecma & Elta / Thales) as mentioned in my earlier posts, these are the fields where we completely failed in LCA development and where we already search for foreign partners, to have these techs ready for LCA MK2.
=> These co-developments will be the base for AMCA!
Again, LCA development hardly gives us more than material and cockpit design experience, that would be good enough for a 5 th gen fighter (see FGFA participation).
Rafale will give us mainly the chance to get into deeper ties with Thales and Snecma for AESA and Kaveri developments, especially since it is unclear how much ToT we will be able to absorb and how long it takes. We can't learn from Rafale or FGFA and develop AMCA at the same time. So either we co-develop AMCA with foreign partners now, or we skip the development and wait till we learned enough and develop it only for the MKI replacement around 2030.