Issuing an online BP (paper or mobile) depends on the origin airport (maybe KTM is a problem) and destination country, or some random personal check.
During covid, it was hard to get a BP because airport had to check documents for entry requirements of the destination, and only a confirmation was issued by airlines.

Before and after covid (when health regulations were lifted), I usually get QR BPs online and do not have to stop at Check-in counter when HBO.

WHen you just get a confirmation, you cannot just show up at the airport 23h before flight and get checked in fully with the BP issued. The staff needs to have the airport system open for your flight, so that they can validate your documents.

The situation where you already have a BP in hands and wish to check your bags very early is a technical different issue.