1. Two prominent male characters are featured later on
2. Fleria's fangirling is only treated as fangirling rather than romantic emotions and Alessa brushes it off like she did to the one woman in ch 1.
3. Everything is incredibly ambiguous even though most yuri authors are pretty upfront when their story is Yuri while Yuri bait authors need it to be ambiguous for more views.
3. The most damning piece of evidence however is that it is simply tagged romance fantasy which is almost always meant to be straight romance set in a fantasy setting.
I pulled most of this info from an old Reddit post as I've personally only browsed through the images of the later chapters and haven't read them. However look at this
chapter and tell me that this is Yuri.
Even without reading any of the text, it'd be very difficult for someone to sit there and claim this is Yuri. There's a small chance their claim would be correct, but when every other book in the OI genre with potential Yuri is revealed to be straight romance, why would you put your trust in this before it's confirmed with a kiss?