That would be a valid solution too! I’m not sure how hard these things are for the Fibery to implement but I can tell you that I just spent almost a full day building a crazy amount of ugly formulas and one-off administrative fields across all my databases to be able to solve this with a single filter on the “All Databases” level. It’s still a manual filter that needs to be changed every sprint until the end of time, but it’s better than nothing.
Formulas in fields would still be my #1 preference as a solution because it would help with way, way more than just filtering and I could see myself using it in many other situations.