Kinda? I think what I have planned is pretty good, it resolves the main conflict of the series. The trouble is that a lot of the other plot threads will have kinda downer endings, but the main conflict is dismantling a giant evil space corporation, it doesn't particularly matter if the MCs are 100% happy because whatever outcome is 10000000% better than what they have before.
I still want to convey that all of the main characters are mostly happy, two of them are travelling the universe together, being romantic dorks (but they will always hold guilt and resentment for the decisions they made), one is discovering who they are and healing from their trauma (after going through a harsh breakup), and another is building a supportive community and delving into their passions (from prison).
It's the sort of ending where what you take away from it is different for each person, and leaves the book open for future stories. If I ever wanted to do a couple add-on chapters, like the couple adopting kids, or the one in prison confronting the former villains, or the traumatised one forming a tenious bond with their family, I could! And it wouldn't be hard, but the main story still stands on its own.