I assume the IWB size/volume won't be much different.They will be overall fairly similar in most respects. KF-21 is 4.5 gen (right now), but it will evolve to 5 and 5.5 gen and then 6 gen etc with whatever blocks and new models that follow etc.
AMCA block 1 will be 5th gen...and also will evolve to 5.5 and 6 gen....its production schedule will lag that of KF-21 for some time as result (along due to the time/resource India spent exploring FGFA JV with Russia for a number of years...that is now dead/squandered essentially).
Other than that (program initial tech tree deployment etc) there is not much difference conceptually in their multirole objective.
Convergent evolution from requirements, expertise and tech tree available on hand played its role in their similarity past that as well.
Good observation.
How's the design for IWB gonna be? Big main IWB like F-22 or have 2 IWB(left and right) like F-35?