People been negative about Denia's fate lately, so I'll share my own thoughts on the matter. A positive view, maybe.
1- Her story 5 tells us that she survived what happened. Denia is alive. Maybe she herself didn't expect to come out of it, but she did.
It also tells us that she absorbed the Fragment, this is interesting because I think this can mean she may no longer need the Pod for frequency regulation if, since the fragment never received GA's message and lost control, it can remain stable within her.
2- So she went into Voidspace and took away all the leftover voidmatter there. Is she lost? Maybe, but I believe she's not.
Her story 2 says she formed a link to Voidspace itself. During MSQ she goes in and out of Voidspace seemingly at will. I add to this the fact that she has the fragment in order to argue that she should be able to just hop in and out of Voidspace and could be back in Solaris already.
I believe Denia didn't choose to end it all, her choice was to no longer run away and do what only she could: free Lahai-Roi from Voidmatter.
Denia chose to not give up, and for that, her story will one day have a happy ending.
WE'LL SEE HER AGAIN. STAY POSITIVE, DENIALINGS. You all matter to me.