Welcome to the Lightroom Community. I'll help you figure this out. You can right-click on the presets & export each preset. Or you could try this:
• Create a Shared Album on the new account.
• Invite the email associated with your old account.
• Ensure you give the old account Can Contribute rights.
• Accept the invite associated with the old account and sign in to the old account.
• Add images with each preset to the Album shared from the new account. This will transfer photos over, including presets.
• Save edits on each image as a preset.
Let me know how it goes. Thanks!