This is the kind of request that makes the limitations of traditional spreadsheets painfully clear. The user has a master list, needs to distribute filtered views to different teams or entities, and wants those views to update automatically when the master changes. That is not a feature request. It is a description of how data should work in the first place.
The workaround described here, manually updating each sheet when new accounts appear, is not a workflow. It is a tax on attention. Every time you add a row to the master list, you have to remember which external sheets need that row, navigate to each one, and paste it in. Delete an account from the master, and you have to hunt it down in every connected sheet to remove it. The user is wise to reject this. They know a formula can pull data, but they also know that formulas break when the structure changes. Power Query and pivot tables solve different problems. The user does not need to reshape data. They need to publish it.
The practical answer is a system where the master list acts as a single source of truth, and every connected sheet is a live filter on that truth. When you add an account to the master, every sheet that should see that account receives it automatically. When you remove an account, it disappears from every sheet that should not see it. No manual updates. No broken references. No checking whether the data is current. The user should not have to think about synchronization at all.
This is what AI-native spreadsheets are built for. They understand the structure of your data and the logic of your filters, so they can maintain those relationships across sheets without you scripting each connection. The user's scenario, entity-specific views that share some but not all accounts, is a straightforward application of conditional visibility. Define the rule once. The system handles the rest. The user can stop managing spreadsheets and start using them. That is the real transformation.