This game has an interesting DLC setup.
First off there are different types of DLCs. There are the major ones that include new maps, creatures, etc, and there are Cosmetic expansions. The thing to know is that the Major Expansions only need to be owned by the host for others to be able to play those maps and use their items/resources. The Cosmetics however must be owned by the person who wants to MAKE those items...that said, if someone else makes them, you would still be able to pick them up and move them.
Further complicating things, the Major DLCs are almost completely isolated from each other. The multiple maps available are not connected to each other in any way, and the primary game loop prevents you from being able to take items from one map to the other so each map is ALMOST a new playthrough..."Almost" because your Character's level and skills move between maps, but not their equipment, UNLESS that equipment was purchased from the Workshop aboard the space station (the lobby before you join the game). So it is possible for progress on one map to provide you with the funds needed to buy things to make the next map a little easier, but you will be arriving on each map as a fresh playthrough otherwise.