Can I help? Not a Hindu but covered this during my RE degree as an area of interest: I ahve 2 sn kids.
The issue is that there are levels of Hindu faitrh. There is tre highly learned brahmanical version which I will explain later and which is the definitive variant, and this view isn;'t what they say. As with any massive faith though there has developed a version called 'Village Hindusim' which is a simpified version in some ways. See if I can explain- well you have a trinity in Hinduism, and all gods are spects of one big Brahman God. That's th pure Brahmanical faith. Village Hinduism tends to be the sort that sees the gods as separate though,: its no small difference, it effectively has a part polytheistic branch and a part monotheistic branch.
Monotheisc is the one that relates to the Bhagavad Gita etc.
Anyway karma.
karma means different tings in different religions and theat has led to confusion: some people for instance see the Jainsm beleif that akrma is like sticky stuff that actually glues to yu.
but it isn't.
AKrma is about fully developing our personality, learning all aspects.
So you might say a disabled eprson was very independent in a past life and needs to learn dependence, or somesuch.
there is however no court of karma where mr and mrs karma sit down and decide who ahs been bad and to punish: that'sa view held by opeople who have no business to be teaching the subject IMO.
karma is about thw hwoleeprson, about eprsnal development. It's a beautioful notion, not a cruel one- eventually and with different timescales it enable us all to develop our potential to be whole, and thus released from this world to become part of that absolute Brahman light from which we originated.
(I am not Hindu btw).