Karma is supposed to be about ethical causality more than anything else. Per Wikipedia:

The theory of karma as causation holds that: (1) executed actions of an individual affects the individual and the life he or she lives, and (2) the intentions of an individual affects the individual and the life he or she lives. Disinterested actions, or unintentional actions do not have the same positive or negative karmic effect, as interested and intentional actions. In Buddhism, for example, actions that are performed, or arise, or originate without any bad intent, such as covetousness, are considered non-existent in karmic impact or neutral in influence to the individual.[24]

Another causality characteristic, shared by karmic theories, is that like deeds lead to like effects. Thus, good karma produces good effect on the actor, while bad karma produces bad effect. This effect may be material, moral, or emotional – that is, one’s karma affects both one’s happiness and unhappiness.[21] The effect of karma need not be immediate; the effect of karma can be later in one’s current life, and in some schools it extends to future lives.[25]

The consequence or effects of one’s karma can be described in two forms: phala and samskara. A phala (lit. ‘fruit’ or ‘result’) is the visible or invisible effect that is typically immediate or within the current life. In contrast, a samskara (Sanskrit: संस्कार) is an invisible effect, produced inside the actor because of the karma, transforming the agent and affecting their ability to be happy or unhappy in their current and future lives. The theory of karma is often presented in the context of samskaras.[21][26]

Karl Potter and Harold Coward suggest that karmic principle can also be understood as a principle of psychology and habit.[17][27][note 2] Karma seeds habits (vāsanā), and habits create the nature of man. Karma also seeds self perception, and perception influences how one experiences life-events. Both habits and self perception affect the course of one’s life. Breaking bad habits is not easy: it requires conscious karmic effort.[17][29] Thus, psyche and habit, according to Potter and Coward, link karma to causality in ancient Indian literature.[17][27] The idea of karma may be compared to the notion of a person’s ‘character’, as both are an assessment of the person and determined by that person’s habitual thinking and acting.[10]

With this in mind, karma is actually fairly materialist if you ignore the parts about future lives. Intentionally doing good deeds which results in good deeds being materially actualized leads to positive change within the person which further incentivized that person to continue doing good deeds. Almost all virtue ethical systems like Confucianism would agree with this formulation. Doing good deeds (as defined by that particular virtue ethical system) leads to cultivation of virtues (as defined by that particular virtue ethical system), which leads to further good deeds, which leads to further cultivation and so on.

There’s multiple dialectical relationships:

1. The dialectic between an individual’s intention and an individual’s good deed (good intentions vs good works)
2. The dialectic between the performance of the good deed and the good deed’s actual impact on the material world
3. The dialectic between the good deed’s impact on the material world and the individual being transformed by the good deed as well

Karma mischaracterized as some cosmic force that rewards good deeds and punishes bad deeds is just orientalizing Westerners shoehorning their familiar conception of God into something that has nothing to do with it at all.