I love seeing Oni mentioned in discussions about Bungie. It's always held a special place in my heart.
Did you ever check out the Anniversary Edition mod? It's a massive community-made enhancement to the base game that adds a ton of fixes alongside a really dope mod framework. The reason I bring this up is because it allows for stuff like Oni Team Arena[0], a fake multiplayer mode that lets you basically play team deathmatch with bots. It's super fun and when I first played it, it breathed a whole new life into the game for me.