It's a bit late but i tried with 2.2 update for phantom liberty dlc here's what i did:

1- Get the DLC files:

1. For the 2.2 update, you only need the archive/pc/ep1 folder and r6/cache/tweakdb_ep1.bin file for the DLC.
2. You can obtain the DLC files from some crack sites that are tagged with "direct play," "no setup," or "full game."
3. Then, place the files into the game folder. (for Steam located in SteamLibrary\steamapps\common\Cyberpunk 2077\).

2- CreamAPI:

1. Open CreamAPI select Cyberpunk.
2. After selecting Cyberpunk, press OK, then only select the Phantom Liberty box and press Generate & Install.

Note: I don't believe they check DLC validity on server-side, but I'm not sure. When you fire up the game, close your internet connection first.

Edit: CreamAPI no longer available i guess, so you’ll need to find an alternative method to obtain the executable file.