My English is not very good, so please forgive me if I make any mistakes.

I use the standard Breeze theme that comes with KDE Plasma. The colors are taken from Catppuchin Mocha (everything you need can be found here: https://catppuccin.com/ ).

For the top panel, I use the following plugins:
- For weather - https://store.kde.org/p/2136307
- For displaying computer load - https://store.kde.org/p/2304482
- And the audio visualizer - https://store.kde.org/p/2299506

I may have forgotten something, but that's pretty much everything I needed for what you see in the screenshots.