I still hope the real love interest is auntie Chen. The mom has never really shown a particular interest in Ren, though in this last chapter Ren does seem to show some interest in the mom. I just think Chen finds Youzi's shipping entertaining and is encouraging it here to tease the mom because she thinks its funny and cute. But I think the mom likes Chen and Chen just hasn't really thought about it much besides she wants the mom to be happy.
The mom is distant with Ren because they have clear history. That's why she's keeping a distance, because there's past heartbreak there.
Chen is just a friend. I'd put money on it.
I wouldn't really say she's keeps her distance. She goes to her shows and even sang with her at one, she buys a bunch of her merch for her daughter and lets her daughter take her vocal classes. I just don't think the mom herself seems very interested, beyond just in a friendly way. If there is a romantic history from college I think the mom has long moved on.
I mean she keeps her distance emotionally.
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch07#3
Mom is visibly shook in this scene. I mean, leaving her reactions aside, spending an entire large panel on the moment they see each other again, narratively, makes sense only if there's something there. Note Chen hasn't had anything remotely like that moment. Afterwards, Mom clearly has her guard up. She's minimizing and downplaying her own importance. She won't take up the invitation to the concert herself, she'll bring Youzi. She's clearly trying to keep her at arm's length, emotionally.
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch02#5
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch08
Notice while she never denies being into girls overtly, she DOES always try to shut down the conversation immediately when Ren is brought up. Very defensive. She is DEFINITELY not over her.
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch03
When she goes to her concert, she buys her a huge bouquet of roses, but then signs them as being from Youzi. (also she blew off the producer of her film to go to the concert.)
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch04
Also interesting choice of pillows to cuddle there, Mom.
All in all, I get the impression that she's constantly caught between showing affection and wanting to avoid opening herself up. And yet we do occasionally get glimpses of their history and the emotions behind it on multiple occasions.
And on the other side, you've got stuff like this:
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch09#3
Ren is plainly doing something she normally avoids just for the chance to see Mom again.
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch07
And they both hung onto the song they wrote together in college.
I don't think the mom and Chen are in a relationship right now or anything, but I think the mom is maybe pining. And Chen is maybe that one outgoing oblivious friend that doesn't take any of her hints seriously. That's my hc right now anyway
I don't think there's a single indication that Mom is pining for Chen at all. They're playful and relaxed around each other. And again, from a narrative perspective:
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch04#4
This is only worth it as a joke if it's a misunderstanding.
https://dynasty-scans.com/chapters/my_moms_a_superstar_ch06#2
And given that the gay fanservice angle is specifically a part of the plot, I really doubt the person mom actually flirts with on camera is the one she's actually into. It would be a weird choice to imply that the plebs on the message board know Mom's heart better than Youzi does.