So… they were like lowkey kinda dating but in a platonic bestie I got a crush on you but let’s not act on it sorta way? But then they kinda broke up in a let’s break up even though we’re not dating sorta thing? Kinda sorta maybe?? I’m getting confused.
Exactly, it's pretty explicit too
"I thought I could always be her light, so she could stay by my side as I march onwards"
"Then what if I dont want to be just fr-" - "No, you can't"
"If you reject Youji, she gonna be taken by someone else" - "Maybe so, but I still want to be able to walk side by side with her"
"Time is a magical time, it can make you forget the feelings that were once so intense"
But when then time passed, after years of separation and 14 more years (little Youzi age):
-Ren's songs still remain as Youji favorite songs, the only songs that Youji could remember who the singer
-Youji still remembers Ren's small habit mannerism like "Ren rubs her finger when she lies"
-Ren confessed to little Youzi that she "do like her mom" and told her to keep it a secret
So you could say their feelings were so intense that it still there after decades passed, but while Ren fully awares of her feelings, Youji can't seem to have the courage to look at hers, I guess it because Ren once left her so absurdly