I'm not clear whether this is a national or international project, and if national, which country. I am very much in favour of such projects if well done, but a bit concerned about duplication of effort with several people developing similar apps, all with different diagnostic, symptom and activity tracking strategies. It gets a bit confusing as a patient deciding which one to try. I hope there is some coordination between developers, leading researchers and leading ME/CFS patient organisations.
Projects like this usually work out when data can be shared across teams and organizations. But health data is never shared, so all we end up with is multiple siloes. I used Visible for a few months, then gave up because, really, what's the point? We need a revolution in how health data is used, but it's going to have to be far more fundamental, likely driven by AI. Otherwise things just get stuck by human obstacles.