That sounds frustrating and I'm afraid we'll need to have a sample clip and/or some technical details to help.
Did you upload directly to YouTube from PD or did you first produce your project and then manually upload to YT? A screenshot of the Produce page screen would be very useful so we can see the quality settings you used.
Use
Alt+PrintScreen or the Windows snipping tool (
Win+Shift+S) if you have Win10/11, then paste it into Paint or any image editing app then save the image as PNG or JPG. Click on the Attachments button below the forum's text box to upload and share it here.
If you're comfortable sharing one of your source clips and your produced clip we might be able to figure out what's going wrong and make some suggestions.
You can also try the Profile Analyzer tool on the Produce Page to make sure PD produces at the highest quality for your source clips. However, it's possible that something about how your source clips are recorded may cause problems which is why it might help to share one here.