Two Capacities With Same Data

I have two Fabric capacities: one for internal reporting and one for external reporting. The goal of this setup is to avoid having internal users affecting external.

As it turns out, the data for the reporting is the same. The current thought is to bring the data into a Lakehouse and create two semantic models from it, "Internal" and "External", that exist on their respective capacities. This avoids data duplication and does not allow internal to affect external (and vice versa). With this setup, however, I am unsure if internal and external are truly separate because all interaction/usage ties back to the capacity of the Lakehouse (per Solved: Re: Usage Across Multiple Capacities - Microsoft Fabric Community). This solution is the only resource I have found on the matter, so if there's an idea I'm missing please share.

How would you suggest handling this scenario? Is duplicating the data the only option to keep a true split between the two capacities?