DS3 ends on a cliff hanger and the Awakened DLC ties up the ending. If the dlc is really cheap and you are certain you will push through DS3 then that dlc is worth it. There is no point to the weapon or resource dlc. If you make sure to explore and drop the resource bot, you will have more than enough resources to make weapons. To me Dead Space is analogous to the Alien series. The first one is slow, creepy, and really deliberate. The second one is faster, bigger, and flows really well. The third one doesn't know what it is and has a hard time figuring it out. If you marathon this series, i would suggest you try to wrangle a friend into playing coop in DS3, so that at least there is a bit of something new.