Let me send you my own nerding out about Cell to fill your motivation genkidama.
In my Perfect Cell comes back AU (that exists mostly in my head and in a few RPs with friends) he gets brought back by Red Ribbon stealing the dragon balls, and makes the simple calculation that the path to perfection actually lays in joining the Z-Fighters. Former villains like Piccolo and Vegeta grew to insane new heights with the gang, so if you can't beat em, join em.
His turn to good starts purely selfish and calculated, and he definitely doesn't crave connection to give meaning to his incredibly nebulous purpose.
Oooo~
That would make sense and is a pretty smart idea. Though I imagine he was very reluctant to work with them at first, but ya know the saying, "Keep your friends close and your enemies closer," lol.
Cell in my AU thinks along those lines at first, just playing along with this whole redemption/punishment plan Goku’s got him doing, but really is just biding his time and getting more in their favor, earning their trust to eventually train with them in order to get on their level, if not further, so he can exact his revenge. But it doesn't really work out that way the more time he spends with them. His resolve to kill them and blow up the planet falters slightly over time the more he lives in it and ACTUALLY experiences the act of living.
Slight side rant, speaking from Abridged specifically here, but I found it wild how he'd go on about earth, calling it a "dunghill" and a "boring blue ball of dirt and water," and I'm just here screaming at a screen like BITCH! You're only 6 years old! You spent 4 of those years buried underground, and before that, you were merely a fetus the size of a peanut floating in a tube! And besides getting your ass handed to you on the seventh day, you stood in that ring for the previous 6, DOING ABSOLUTELY NOTHING!!! (I know in original dbz he destroyed an army and went up into space to train and blasted some asteroids during that time, again, strictly referencing abridged here) Damn bug has no legs to stand on saying that shit when he's barely lived at all.