Work with Salesforce Orgs and Users
Most businesses have multiple Salesforce orgs for specific purposes. Similarly, a Slack user can be on multiple workspaces and can have access to multiple Salesforce orgs.
What does interacting with a Slack app look like for a user in a single workspace or multiple workspaces?
An app can be installed in multiple workspaces for multiple users and connect to the same org.

Multiple apps installed in a workspace for multiple users can also connect to different orgs.

Connecting a Slack app installed by multiple users in a workspace to different or multiple orgs isn’t supported yet.
You can build multiple Slack apps that all interact with the same managed package in the same namespace. You can have multiple SlackApp records in your package, but they must use unique developer names.
This feature is not generally available. It is not part of your purchased Services. This feature is subject to change, may be discontinued with no notice at any time in SFDC’s sole discretion, and SFDC may never make this feature generally available. Make your purchase decisions only on the basis of generally available products and features. This feature is made available on an AS IS basis and use of this feature is at your sole risk.