Thanks @Forpli @Aravisian, after a long long trial; I managed to put a modern + zorin-like dark theme and added some features for Dolphin:
Compared to Nautilus, this Dolphin has these features:
- Show hidden items with a different color
- Select predefined icons for folders (similar to Windows)
- Show recently accesed folders (not just files, none of the file managers had this feature)
- Show folder content thumbnails + previews (similar to Windows)
- Run desktop files
- Start file manager from the latest state (windows,folders,tabs) on startup
- Support typeahead search instead of searching recursively on all subfolders when you press a key
- The window content doesn't dim when focus is lost (unlike nautilus on zorin theme)
- It doesn't lag randomly unlike nautilus (Look: nautilus-is-not-responding issue)