Samsung has answered the prayers of many users with the Theme Park app. Available as a module for the Good Lock app suite, Theme Park can create a theme, based on your wallpaper.
It automatically detects the main colors of your wallpaper and generates a theme. You can choose a different color palette for different UI elements (like the color of speech bubbles), choose a different background color and even pick the icon, icon label and tray colors.
Once happy with the result Theme Park automatically applies the theme to your phone. Theme Park should work on most any One UI smartphone.
The Good Lock app has a number of different modules for One UI customization. You can change the style of the lockscreen with LockStar, change the recent apps UI with Task Changer, customize the always-on display with ClockFace and get a bevvy of gestures with One Hand Operation+.
If you want to use Theme Park, you need to have Good Lock installed. It can be found in the Galaxy Store on your One UI-powered Samsung phone, if you live in a supported country.