Hello, thank you for reaching out to Microsoft Q&A.
Is it possible that your Photos or videos are syncing from your Windows 11 PC to the OneDrive desktop app?
Right-click the OneDrive icon on the taskbar, select Settings > Accounts, then click Unlink this PC.
So your files will no longer sync and takes up your OneDrive storage.
Regarding your stroage,
With a Microsoft account (without any Office 365 Subscription), you get 5GB of OneDrive Cloud storage and 15GB of Outlook email storage. If you exceed any one of the storage limits, you won't be able to send or receive emails.
To free up your OneDrive cloud storage, go to https://onedrive.live.com/ and sign in with your Microsoft account.
Before deleting the files from your OneDrive folder, ensure you've backed up the folders on your local folder.
Also, ensure you empty your recycle bin folder in OneDrive to delete these items permanently.
Once deleted, it takes 2-4 hours for the storage to reflect into your account.
Let me know if you still need more help.