debt for a nation is not the same as for an individual.

the kind of debt nations want ot have is the one that is created in the effort of improving its own infrastructure and industry, whihc would in turn allow the nation ot generate Wealth that can be used ot pay off said debt(at the veary least pay off the interest)

bad debt for a nation is the one that is created ot do anythnig else other than that.

in this situation the only way you lose faith in the currency is if the nation itself experiences such crippling economical collapse that it makes all major investors panic, resulting in them cahing in to pack their sht and leave.