They haven't updated the Roadmap after the hotfix 1.22 came out, but just imagine the hotfix 1.22 in the roadmap after the hotfix 1.21:
https://www.cyberpunk.net/en/news/37298/our-commitment The roadmap shows the free DLCs will start to come, possibly earlier than the next-gen console version. Sometime in 2021.
For any more detailed timeframe, I think
Crawdaddy79 is absolutely correct: "When it's ready."
For the reason why, I think
JakobFel is right: disastrous launch, a lot of bugs to fix, the lawsuits, greedy ransomware people... All of this delays the DLCs.
I wouldn't be surprised if after getting all the biggest bugs and performance issues fixed, the DLCs will be a bit more delayed because they give the employees some time to ... you know, have time with the family. Cool down for a moment. Maybe relax a bit. They had a long crunch before launch and now they have been working a lot to fix all the bugs. I think some of the devs might need some time off. But maybe they give the devs time off in different times to keep the development going with only minimal delays. I don't know. Just guessing here.