Elementor Sticky Sidebar Issue into clear and actionable steps:
Isolate the Problem: Create a new, simple test page with only the sticky sidebar. Remove any extra widgets or complex styling from the sidebar on your original page.
Test and Simplify: Check if the jumping/flickering happens on the simple test page. If it doesn't, the problem is likely with other elements on your original page.
Fine-Tune Elementor Settings: Carefully review Elementor Pro's sticky settings (offset, z-index, etc.). Experiment with slight adjustments to see if they improve stability. Check for elementor updates.
If the problem is not solved by this method then check for Elementor Support.