iPhone space vs iPhone storage

You ar confusing iPhone storage with iCloud which is Apple's synching service. Your phone will always have the same amount of storage it came with. Yours appears to be filled with 'Other.' The only way to create more space on the phone is to delete photos, messages, apps, etc. Be sure to save important photos and data to your computer or an external drive. Check these links....

What's the difference between device storage and iCloud storage? - Apple Support

Clear Other storage on your iPhone or iPad - Apple Support

This video may help...

No, your paying for iCloud storage, phone storage is a fixed size and can't be increased.

The difference between phone storage and iCloud storage -

https://support.apple.com/en-us/HT206504