It is not possible to delete photos from the library, but keep them in the albums. The library is the place where all photos are stored.
The albums are not storing your photos but are using the photo in the library. The albums are just an index to the library.
As a work-around: When you want to distribute your new photos too albums and easily see, which photos have not yet been added to albums, add all new photos to an album of your own. Name this album for example "My Recent Photos". Then distribute the photos to other albums starting from "My Recent Photos". Once you have added a photo to a different album, remove it from "My Recent Photos". It will stay in the other album. Proceed, until "My Recent Photos" is empty.
Or tag all photos you have added to albums with the favorite heart. Then you can see at a glance, which photos still need attention.
I am using the Shared iCloud Photos Library to to split my Photos Library in two separate sets of photos - the photos I have organized in albums, have been edited and are tagged with titles will be moved to the Shared iCloud Photos Library. They will remain in their albums, are no longer visible in the library, when I am viewing my personal library. The Personal Library is the construction site with the photos that still need attention, while the Shared iCloud Photos Library is the exhibition room with the finished photos, see: Using the Shared iCloud Photos Library to have two separate libraries on all devices - Apple Community