I like the possibility to have all pictures in the cloud.
But I have to use the "old" Lightroom Classics because I miss some features (see Sync Development Changes).
But Lightroom Classics syncs every picture from the cloud to "Lr mobile" (like mobile uploads)
I'm not able to limit the space or select the albums.
And I have not enough space (in the future...) to sync every original to local disk.
(If I deselect the sync in the album the album is deleted in the cloud...)
Lightroom CC is a fairly new product and we're looking for feedback's from valuable users like you to incorporate as features in upcoming releases to make the product better for user experience. Please share your feedback here Photoshop Family Customer Community so that our Engineers can look into this.
I'll reach out to the concerned team and check if there's a way to prevent this from happening and to save space.
In Lightroom Classic's preferences > Lightroom CC tab, you can set the location of the downloads to another drive, which might help.