Certificate PDF builder etc.. its the worst system. DOESNT WORK

Hi there, getting really tired of this. i read hundreds of negative comments about the certificates but we are too invested to move on and need this to work. First your videos about the addon PDF certificates and builder are really outdated. i Need a certificate with a background image, and name of the person on top of it. plain and simple. To print an A4 with enough quality you need at least 150PPI so we need to use an image of at least 1240x1754 MINIMUM. On your plugin when i create a PDF A4 vertical it stablishes : 595x842 THIS IS NOT ENOUGH. Ok i go and change the size to CUSTOM, and i write down 1240x1754 as mentioned before. I upload the template for my certificate on that exact size. View PDF shows it perfectly. I click Generate PDF certificate, download and get This : https://www.jonhernandez.education/wp-content/uploads/2022/02/sample_82401.pdf?1645708808 Can you tell me what im doing wrong?? cse this is really disapointing. ASAP please