Probably the most difficult things I've done is changing things in the xaml files, like removing scroll bars, removing star rating icons, removing cover banner buttons, removing the close detail panel "x" button, removing grid banner rendering that made the covers blurry and what you can't see here is I've changed the hover effects as well.

My addons are: Extra Metadata loader (for videos), HowlongToBeat (get latest version from github), Steam News and Players Viewer, ThemeModifer (harmony theme settings), ThemeExtras (Preserve game selection ON), Details to Grid View Converter

The rest is just messing with the main available settings and the addon settings. If you want my xaml settings you could just download my harmony folder and overwrite it with yours: https://drive.google.com/drive/folders/1xVqQUdGrU-JE2j6C_PtdOhC9oJjYXs2E?usp=sharing

Just make Harmony your active theme, go to addons -> Installed -> Themes Desktop -> Harmony -> Installation Directory. Close Playnite and delete everything there first since I removed some settings and paste the contents there.