Avoiding multiple thumbnails for photos

I have a question regarding photos on external storage. I have about 150GB of family photos that all users in our nextcloud should have access too. I installed “Preview Generator” and see that previews have been generated for every user on my nextcloud resulting in a disk usage of about 100GB.

Is there a way that I can make these photos available to everyone without having thumbnails for each user separately?

I have a similar issue as this one. In my case, I have photos in an S3 bucket that I’m also making available to all users but the recognize app ends up showing a different “person” in the “persons” section for each user. I’m testing the configuration now with 3 users before rolling it out for use by my entire community and each face shows up 3 times in section. It seems the scan is happening per user and scanning the same S3 bucket repeatedly. How can this be avoided?