Female Homosexuality (cont.)

Hi, this is a follow up on the female homosexuality question from a few days ago. Thank you for responding, I’ll try to be more specific. From the teshuvot I’ve read it looks like there’s a prohibition against women being nasim mesolelot and a second prohibition against their following the ways of Egypt/marrying each other. Obviously women can do physical activities like holding hands and can have relationships that share a few things in common with marriages, like sharing housing, but there are physical actions that obviously go too far/violate nasim mesolelot, and there are relationships that obviously resemble marriage closely/violate כמעשה ארץ מצרים. I understand the categories broadly, but haven’t been able to find a source that explains what the criteria are for either prohibition. I’m becoming unsure that it exists really. I’ve asked the question unsuccessfully but am uncomfortable involving the remaining people I would ask.
Sorry for the repeated question, thanks in advance.