I agree with your first, second, and third points completely. However, for my purposes we are imagining an incredibly unlikely hypothetical world where Tommy simply gives up the discs for no reason at all. So, my argument doesn't really pertain to those paragraphs.

I have some problems with your fourth point, though. From my view, it seems like Dream's actions against Tommy have gotten more and more serious over time. Remember, his actions have gone from holding music discs hostage to blowing up Tommy's country to convincing someone else to blow up Tommy's country to fighting with Technoblade in order to destroy Tommy's country more to manipulating Tommy's best friend to exile him to mentally abusing Tommy in exile to teaming up with Technoblade again to wipe Tommy's country from existence. It seems like Tommy still gives value to the discs, but Dream wants to find better (or worse, I guess?) ways to torture Tommy. I think that Dream will hold Tubbo hostage no matter what condition the discs are in. However, if Tommy gives up the discs (in my hypothetical scenario), Dream will find it a bit more difficult to get a hold of either Tommy or Tubbo. Without direct leverage over Tommy and Tubbo, Dream will have to completely resort to combat to beat them. In the real world where Tommy still wants and values his discs, Dream will be able to hold them hostage and end the fight faster. So, Tommy letting go of his discs will improve things in the short term, but most likely won't improve things in the long term.