I think with this style of traveling, you should do 1 of 2 things when you are searching for a property:
1) Look for an Airbnb with a keycode. Ask the host during the Inquiry or Request to Book if it is ok to check in any time after the designated check-in time. There are plenty of properties that would be fine with this.
2) Stay in hotels, or other places with a flexible check-in.
I understand all of your concerns about having to specify an ETA, that you might have to bother the host by calling to reschedule, etc. I also respect, however, a host’s style and preferences for their particular property. There is no standard or correct protocol. Sometimes it takes a bit of communicating beforehand to find the right fit.
None of this helps you with your current situation, however. Having not asked questions and/or made arrangements beforehand, I think I would try as much as possible to provide a half-hour window of arrival with this particular host, 1 hour at the most.