Good question. I’ve written before about this topic, and I’m not sure much has changed. I’ll copy what I wrote before, but keep in mind I haven’t tried it in a while so it might work with Steam natively now:

I’ve done some research (mostly from Thunderfox’s posts from Reddit) which revolve around overriding steam_api.dll with the one produced by CreamAPI. He says to either:

• Use this launch command in Steam:

WINEDLLOVERRIDES=“steam_api=n;steam_api_o=n” %command%

• Use Steam Tinker Launch’s dll override:

steam_api=n;steam_api_o=n

However, it seems neither of them work.

CreamAPI, as far as I understand, works under the assumptions:

1. Steam is running

2. The dll that CreamAPI produces interacts with Steam (by replacing the game’s default steam_api.dll) in order to unlock the DLC

I think what is going on here is that either:

1. Steam is closed or suspended in the background on the Deck and therefore CreamAPI’s dll is not hooking into Steam (this doesn’t seem likely as other games use Steam to run things like multiplayer)

2. Steam has another steam_api.dll (on the particular Steam version included with the Deck) which is not being properly replaced by the simple winedll commands I’ve listed above.

I should mention that I’ve tried using Bottles by:

1. Creating a bottle
2. Installing Steam on that bottle
3. Installing the game on that version of Steam
4. Replacing the CreamAPI steam_api.dll within the bottle

And it works. However, it’s not convenient and I run into a lot of problems using Bottles and Lutris in one way or another.