That is potentially bad news, as you have effectively booked with, and paid, a third party rather than the cruise line.
With our U.K. TA the payment always shows as direct to the cruise company.
During the pandemic, cancellation refunds that had to come via TAs were very slow,
If the TA goes bust then there also could be a problem.
Finally, credit card companies are less willing to deal with disputes where payment was made to a third party.
With what is going on with Explora you are right to be concerned.