Prototype a sticky bar in Figma that appears after the user scrolls a certain percentage of the page

I’m looking to prototype a sticky bar in Figma that becomes visible once the user scrolls past x% of the page height. The animation should have a smooth slide-up effect to keep the experience seamless. Any ideas on how to achieve this in Figma’s prototyping mode?

For example, a sticky bar appears only when user scrolls to 20% of the page and it will become fixed to bottom of screen for the rest of the scroll depth. Then when a user scrolls back up, the element releases from the fixed position and disappear. You can see this in effect on this page

Does anyone have any solution to this?