I think of it like the xz backdoor. A long time investment of goodwill over months before you tighten the noose.
The more sophisticated attempts seemingly do not straight up ask for cash. They offer an investment opportunity on a scam website which will report the investment doing well, so the victim will independently invest more money.
What does work is an absolute, ironclad rule that I do not trust and am not friends with anyone I meet online until we've met multiple times in person. But there's a lot of lonely people out there who don't find that rule so easy.