> I try a bunch of different OCR programs, but can't find any that can transcribe the document with 100% accuracy. They often confuse certain letters or numbers (like 0 and C, 9 and 4, 0 and D). Sometimes they omit characters, sometimes they introduce new ones. I try different font sizes and different fonts, but it doesn't matter.

I feel like this could be trivially solved by plugging an LLM to the OCR output with the sole task to correct spelling errors like that. That's pretty much one of the tasks LLMs should excell the most at.