The way the model is set up, a zero-CoVID strategy is impossible. If you close the borders and impose a full lockdown on day 1, you still end up getting about 10 cases/day forever (I believe this is due to assumptions about imported cases).
There are, however, countries that have achieved zero CoVID and then reopened and sustained zero CoVID. But this is only possible with strict border quarantine rules, extensive contact tracing and immediate mass testing whenever a new case shows up.
The assumption should also be existing cases of infection that are not yet symptomatic, or are totally asymptomatic. Borders are leaky too, but when the disease was found it was already well distributed, and with a long incubation period.
There are, however, countries that have achieved zero CoVID and then reopened and sustained zero CoVID. But this is only possible with strict border quarantine rules, extensive contact tracing and immediate mass testing whenever a new case shows up.