Indeed, but the OP has already booked flights in a manner that does not allow for a 1- or 2-night stopover (even aside from the fact that one-way itineraries are not eligible for these stopover packages) unless they change the flights already booked, which may not be possible now based on their existing travel plans and which may lead to additional expense.

It's still not clear if the OP is in the "forced stopover" position, but their travel is now booked in this way, and I am advising them to seek advice on whether an eligibility for a hotel arises based on the ticket that they already hold - rather than encouraging them to change their ticket in a manner that won't even get them a hotel (based on the terms of your other offer, it must be a return ticket).

Good to know for future trips in premium classes, though, for those not aware of this facility.

I do not know if one-way First tickets are eligible for "standard" STPC packages, which is why I hope that the OP will ring, ask, and report back.