Are there in 2023 any buses on Route F26 Sprengisandsleið (Sprengisandur Route) via Hrauneyjar, Nýidalur, and Goðafoss to Mývatn? An old tripadvisor post from 2019 suggests there is one bus per week run by Reykjavík Excursions, but their website mentions only Skógar, Landmannalaugar, and Þórsmörk (i.e. for the Fimmvörðuhals and Laugavegur trails where 99% of hikers appear to be heading). It seems Gray Line still run highland buses on the Kjölur Route 35 at least as far as Hveravellir, but they don't run buses to Nýidalur.
I found a map on nat.is which indicates a bus route on the Sprengisandur route, but the map is from 2011 and doesn't indicate specific operators:
It's difficult to find an overview because there are so many different bus operators such as Reykjavík Excursions, Gray Line, Trex, and others. Are there any buses on the Sprengisandur Route F26 in 2023?