In the anime, Rikka is gay toward Akane 100%. The mixing. The gift. The ‘you are born to love me’
Unfortunately Akane acts very indifferent toward Rikka. Maybe she fond of her more than any other characters, but the mutual romantic affection is not quite there
Interviews out right confirmed that Rikka is the only person in the computer world that Akane loves.
https://i.imgur.com/UtJnXDf.jpg
Also, in the most recent interviews in Mook Magazine it tells is that the first scene of the ED is actually in the real world, and we're seeing real world Akane and Rikka. The director also noted that it's not a coincidence that Rikka's Mom, Alexis, and Gridman all have yellow eyes. This is telling us that Rikka's mom is a being from the hyper world. Which means she can travel between the computer world and real world.
It's fairly safe to assume that Rikka from the real world and Rikka in the digital world are one and the same, and that her mom brought her there to save Akane.