On an iPhone 15 Pro Max
From Apple Support:
Thank you for using the Apple Support Communities! We understand you're looking for a way to quickly jump to the bottom of a note within the Notes app on your iPhone.
To accomplish your action outside of scrolling, you can tap and hold on the side scroll bar that appears to the right inside of the note, and drag it to the bottom of the note. Otherwise, there is not a specific function available within Notes that can jump to the very bottom quicker. We do encourage you to share feedback to Apple to provide your suggestions:
Product Feedback - Apple