Hi there oumey,
From what we can tell, the device storage on your iPhone is almost full, and you're asking how to manage your storage so that you can use your iCloud storage, rather than your device storage. We're glad you're here, and we'd be happy to provide some guidance.
To start, it looks like a significant amount of your device storage is being used by Photos. We see that you've turned iCloud Photos on, but the upload to iCloud appears to be paused because Low Power Mode is turned on. Low Power Mode pauses uploads to iCloud Photos. We’d suggest turning Low Power Mode off in Settings > Battery. Learn more about Low Power Mode here:
Use Low Power Mode to save battery life on your iPhone
After turning off Low Power Mode, let's try finishing the upload to iCloud Photos, then turn on Optimize iPhone Storage in Settings > Photos. Have a look at the links below to learn more:
Manage your photo and video storage
Also, the suggested steps in this link may help:
How to check the storage on your iPhone, iPad, and iPod touch
We hope this information is helpful. Don’t hesitate to let us know if you have any more questions.
Cheers.