If you like writing your own prompts and experimenting, https://astria.ai can do this kind of thing too.
So, if you really want to reproduce this on your own without using a service like ours, I would advise to: i) train a model with Astria, ii) download the model checkpoint from Astria, iii) install Automatic1111 UI with the ControlNet extension and now you will have a local setup that is very close to what we have, the only missing piece is that we have a custom model optimize for faces.
For example, Astria has its own trick to increase the number of headshot in frame, if you download the checkpoint and run it locally you will see that it doesn't handle well negative prompts (which, IMHO, is usually a side effect observed on fine-tuned style models with dreambooth). With this trick you can get up to 70% of headshots in frame but won't reach 100% without risking a loss of prior knowledge. This is my experience so far, maybe you have another opinion based on your experience.