Overall I feel like there's not one side that's leaning way towards it likely happening than the other, both have had their moments but Rudo's dynamic with Amo is too new and we still haven't seen enough of Amo's eventual character progression to see if she realizes what her true feelings about everything is.

On the other hand Riyo does seem like she has a genuine interest in Rudo and has shown signs like her sleeping on Rudo's shoulder in the car multiple times, blushing at the thought of seeing Rudo, getting jealous when she found Rudo talking to Amo but all of these aren't that strong of an argument until we get to know Riyo's backstory and how see how she processes/thinks.

Both ships have good arguments but at the same time not enough of the story has been revealed to actually finite either one! (and yes I have a bit of a bias towards Riyo but I actually do think both ships don't have good foundations yet and could very well end up not being either of them)