There are several threads per day on roughly the same facts. FT is a microcosm of the universe of travelers, so the issue is broader.

The simple fact is that booking Norwegian is a mistake.
1. At best, one has to worry even if things go smoothly.
2. Cancellations are routine and rebookings are expensive and inconvenient, e.g. out of other airports.
3. Compensation for cancellations & delays, reimbursements for downgrades, and even duty of care expenses are nothing to count on as the carrier may well be insolvent before any claim is paid. In that instance, all one has is an unsecured claim and the chances of collecting anything significant are at best, slim.

If one is insistent on booking Norwegian, one ought to have high end comprehensive travel interruption, reimbursement, and incidental coverage as a hedge. Remember that the least costly ticket is not necessarily the least costly journey.