For reviewing schematic/boards I recently developed something for internal tests:
1. A frontier model (either Opensource or closed source) gets a load of text to review a Kicad project systematically
2. The frontier model can extremely "ask" a cheap Gemini vision model to give it data from datasheets or specs.
Main problem: the quality dramatically hits the shitter done once it falls back to "pdf2latext" due to complex tables.
It was even able to do complex ngspice simulations. But you must offer it all datasheet PDFs.
$1-2 of tokens saved me from $70-80 bugged PCBs.
Not sure why the complicated setup with Gemini. I assume you are on a Codex or Claude plan (100 or 200 EUR/USD/m). The model will just pull datasheets and use a combination of conversion to text and looking at bitmap renderings of the PDF. Haven't had that dramatic quality issue you mentioned. When the model isn't sure, it will just keep looking until it understands the datasheet clearly. But yes, it needs the datasheets.