My extremely uninformed and non-professional take is that communism only really works on small scales. at a small scale, maybe less than 150 people, what actually needs to be produced can be handled by a few people who understand the needs of the community, or people can present what their own needs are and others can help them. For incentives, pretty much the only one is dopamine like you said, but helping out in a community and seeing the impact should not be underestimated as a motivator, and neither should reciprocity (I got helped so I’ll help other people).

Larger than that you’ll need an organizational structure to handle needs and potentially an enforcement structure to handle motivation or lack thereof, inherently leading to people with more power than others who might abuse that power to garner more of it.