There is a lot of interesting research into predictive coding as an alternative means to solve the credit assignment problem that might be a more plausible model of what happens in the brain.
I really liked this paper that showed using a predictive coding learning rule leads to the exact same gradients as backprop in arbitrary networks:
Predictive Coding Approximates Backprop Along Arbitrary Computation Graphs https://direct.mit.edu/neco/article/34/6/1329/110646/Predict...
That was genuinely a strong signal that whatever learning algorithm the brain uses isn't "magic", and probably can be approximated with the ML tools we have.
It also pointed at the possibility that the learning algorithms brain uses might be, like the paper has demonstrated, less compute-optimal and data-optimal than backprop - but far easier to implement in a localized, distributed fashion. Because backprop requires activation storage and global connectivity - and both "hot" data storage and connectivity of any kind are extremely expensive for the brain.
This paper uses the "fixed prediction assumption" so I think has caused some confusion (i.e. it's not PC, but PC with a small bandaid). It's a great paper though just the title is misleading somewhat. But all of Beren Millidge's papers are quite good and he was so prolific in the space. Cool to have seen him on the Dwarkesh podcast recently as well.