Greetings Vregat,
The screenshot shows you have 11 items not synced with iCloud. If you have large videos waiting to upload, then it's likely that 1.6GB is not enough available iCloud storage, and you may need to upgrade. Check out how here: Upgrade to iCloud+ - Apple Support
If the items waiting to upload are smaller files, such as photos, then see if a Smart Album named Unable to Upload has been created with the photos that did not upload. Select one of the photos in the album, apply an edit, and then see if the photo uploads to iCloud as expected.
The following article shows how can you apply an edit to see if that helps with uploading to iCloud:
Edit photos and videos on iPhone - Apple Support
"Straighten and adjust perspective
- In Photos, tap a photo or video thumbnail to view it in full screen.
- Tap Edit, then tap .
- Swipe left under the photo to view the effects you can edit: Straighten, Vertical, or Horizontal.
- Tap the effect you want to edit, then drag the slider to make precise adjustments.
- The level of adjustment you make for each effect is displayed by the outline around the button, so you can see at a glance which effects have been increased or decreased. Tap the button to toggle between the edited effect and the original.
- Tap Done to save your edits, or if you don’t like your changes, tap Cancel, then tap Discard Changes."
Kind regards.