Hello k_et,
It sounds like you deleted photos from a shared album, but the photos are still showing in the album, correct? We'd like to see how we can help.
Just to make sure we're on the same page, did you use the steps outlined in the "Delete from a Shared Album" part of the previous link to delete those photos? How to share albums in Photos on your iPhone, iPad, and Mac
"If you're the owner of a shared album, you can delete any photos, videos, or comments from anyone. Subscribers can delete anything that they personally added. Anything you delete is automatically deleted from the album on all your devices and the devices of subscribers.
Any photos that you saved or downloaded from a shared album to your Photos library stay in your library even if the shared album is deleted or the person who created it stops sharing it."
Before deleting any photos, please make sure that you save any photos that you want to keep. More about that under the "Save photos and videos from a shared album" part of the above link.
If shared albums aren't working as expected, the information and steps here may help: If Shared Albums aren't working
Thanks!