I thought we had a pretty good understanding of this up until the molecular and electron level.

Am I missing something?

My daughter did her research in this field while an undergrad, and explained to me that photosynthesis is not yet well understood. Some of the theories of the mechanism are discussed here: https://physicsworld.com/a/is-photosynthesis-quantum-ish/

How photosynthesis works at a cell machinery level is high school level biology.

That's not an understanding of how it works

I disagree. It very much is an understanding of how photosynthesis works, it isn't a complete understanding sure, but an understanding nonetheless.

Unless you're going to argue that we don't know how an MRI works because we don't fully understand the physics behind superconductivity.