So, i looked everywhere to download themes for Kdenlive but there were no websites to get more themes for Kdenlive. Not even the KDE Store has Kdenlive themes. I remember back then, you could found more themes for Kdenlive by going to the KDE Store and download some themes but not anymore. Where can i find more themes for Kdenlive?

you have to search on PLASMA colors schemes...
here my theme: https://store.kde.org/p/1237458/

the path of themes is this: kdenlive\bin\data\color-schemes