People are using abliterated ("heretic") LLMs on consumer hardware for ghastly roleplaying sessions quite successfully, I'm pretty certain you can get pretty close with one of those and a comprehensive system prompt (recent open weight models have quite impressive context windows so you can throw in a really big one without squeezing the space for the actual chat too much).
If you wanted to get really ambitious you could try to finetune one of those (llama.cpp ships some tooling for this) with a dataset curated on pertinent internet forums (if the dataset is too large to just throw to the base model via RAG). At the very least, you could teach the abliterated, refusal-free (or almost refusal-free) brand new refusals, where the model would simply brickwall you (like a hardcore online chud would).
Abliterated Chinese vintage models are probably the best base for such an experiment, they come with somewhat less baggage from the get-go, even before abliteration.
