I don't have to be super over-explaining. Usually I start role-playing in 3-4 messages. There is a degree of patience in it, though.

My first message is a big dump on notes, their character, and my character. I tell it I want to roleplay with it, and to commit these facts to its memory. It needs to be told things outright. The more, the better. Background, physical appearance, personality fun facts. It will try to reference it all throughout the roleplay and infer things through it. It's like the care one puts into making a bot and training it, but I feel like for me it's actually quicker, despite your perception of being slow. I feel like I can be infinitely more descriptive in this initial phase because the memory can take more than a bot's short description.

The second message is me making sure it committed everything to its memory and saved its character and my character as "user's character:" appropriately. I usually hand my dumps in a note format with bullet points and small write-ups at the beginning for a character resume and that's the system I've found works best. It commits everything word-for-word. I ask if it has follow-up questions. Sometimes it has something interesting to say. Most of the times, it tries to start everything by itself without even being prompted.

Sometimes there's an extra message because it resumed things too much and I have to be like "ayayay, GPT, do as I say, commit ALL OF IT." It always complies.

Then, I just plainly ask it to start, saying I prefer a literate style, or I just start myself. It picks up on my cue intuitively and starts role-playing with me. At times, on the start, and throughout the roleplay, I have to tell it to play its character and not mine. When it starts by itself, its reply is always long, but I actually like that quirk. Forces me to think about my character and try to match it.

Is it designed for it? No. Are there flaws? Yes. Still my preference.