Is there a good OCR is good for some weird data (not natural language), such as a screenshot of a base64 encoded file. There was a CTF challenge requiring you t

Is there a good OCR is good for some weird data (not natural language), such as a screenshot of a base64 encoded file. There was a CTF challenge requiring you to recover full RSA private key from a partially redacted screenshot of a RSA private (pem). I tried serveral OCR tools to try to extract the remaining base64 characters. I did tried to use Tesseract too, but the result is quite bad. I used GCP's OCR service eventually, the result is almost perfect for this task, but I wonder is there some non cloud-based tools are good for this task?