Good day. Me and my friend really wanted to try to get all the vanila zombie maps for black ops 1, just to get proper chronology of the events of the lore. However the game is still 40$ and each dlc is 15$ which is outrageous for 13 years old game, and each dlc is just one extra map. Eventually we do get blacks op 1 on sale but decide to skip purchasing DLCs as they cost far more than the game itself. We tried to find run around the issue and found this solution shown in this video - https://www.youtube.com/watch?v=4JDbZT8m6f0
which gets us all the DLC maps but we can only play them offline and Steam automatically kicks us whenever we try to play them online.
 
Unfortunatelly we can't play black ops 3 due our PCs can't handle it. Plutonium isn't an option either because it demands to own windows 10 which we can't have either way, and plutonium comes with it's own pack of bugs and crashes, like server\game crash after picking CZ75 pistols. We were thinking if it's possible to somehow launch these DLC maps as separate "mods", just so we finally can play them together. Alternatively, we would be thankful if you tell us about mods of these DLC maps that doesn't alter gameplay and lore at all, especially if they provide a lore-friendly Easter Egg endings.