Can we use Lightroom as a collaborative tool?

Can't be done. Best you can do with Adobe tools is to put images on a shared corporate folder and use Adobe Bridge together with camera raw. You will be able to collaboratively keyword, edit, etc. It is basically Lightroom Classic but it is a file browser instead of a cataloguing program and edits are stored in xmp sidecars so can be read and edited by everybody with access contrary to Lightroom CLassic or Cloudy. You can create collections in Bridge but I don't know if you can share those. 

I don't believe it's possible unfortunately.

The closest feature to it is to share albums, with rights that you can set for each individual user. And although there are preferences for them to edit and contribute, I don't believe (even with editing rights) it's possible for all users to add and change keywords and rate images.

Even if we could have Share Folders, that would be a step forward but the other limitations would remain.

I think that and hope that the team can develop better collaborative options as these, and sharing have taken a back seat for a while now.