You will need to install a user script manager extension to install this script.
When video is playing and you stop moving mouse pointer, YouTube hides controls, but I believe the progress bar should still be visible at the bottom. That's what this script provides, like in the image below. Buttons like play/pause are still hidden, only progress bar is always visible.
Initially based on https://greasyfork.org/en/scripts/30046-youtube-always-show-progress-bar.
Created this to provide compatibility for videos with chapters.
Tested with FireMonkey and Violentmonkey.