In user settings allow coaches (and athletes) with appropriate warnings to set a starting CTL and ATL, ideally per sport, that will be used for athletes that are unable/unwilling to import their previous 42 days of workouts. As an experienced coach I can take a reasonable guess from an athlete's first week of training combined with an interview or 'stalking' on a certain sports social media app.

I realise the PMC has this, but if you set the PMC start ATL/CTL in coach dashboard it applies the same values to every athlete.