Could someone help me? Do I need to set up different shipping profiles for costs, or is it enough just to have the store linked to PrintShimps? I hope that makes sense.

Hi all, I had already uploaded some prints to Etsy but suddenly realised I hadn't double checked file quality. I have spent HOURS today trying to get just one poster to an appropriate size. I thought I was getting somewhere but I've just run my pdf through a checker and it's showing only 1634.88 x 2293.12. I feel completely defeated! Let me explain the journey. I had an image in Midjourney, used subtle upscale and then exported to Upscayl where I used Upscayl standard and jpg (made the mistake of using a PNG file at first but file size exceeded 130MB). The image size showed as over 8000 x 9000 px. I updated my poster in Canva. When it came to downloading I couldn't do it as a PNG file as was restricted on size as I don't have Pro, the max I could download to as a PNG was 1587 x 2245. Instead I downloaded as a pdf flattened. I can't see the dpi for the pdf but when I zoom in the quality looks great but somehow the file size is only 1634.88 x 2293.12!!! I feel like I've wasted a whole day and got nowhere. I've searched in here and seen lots of great advice from previous posts. I 've been on chatgpt and doing as much research as I can but still left with a file I just can't use. So sorry for the long post but any step by step help would be SO appreciated. I feel like I'm learning a new language and completely failing! Thank you. P.S As a side note, I've seen that Print Shrimp prefer files in PNG but how can this be achieved without paying for canva pro as the PNG file size is limited.