Deleted Conversations on iPhone not deleting on MacOS (Sync issue?)

I am getting TONS of spam texts. I am reporting them to help reduce them, but Apple could have some sort of spam filtering based on phrases or words (I realize this is for another topic).

However, what's really bugging me is that after I've deleted the spam text "Conversations" on my iPhone, I then have to go to my MacOS and delete them again and this is just ridiculously time consuming.

Do I need to have my messages on iCloud in some way to have this sync properly? I'm not sure what my settings should be, or if this is just an issue with the MacOS (doubtful).