Struggling With Whether to Keep a Problematic Player in My D&D Group -> Please Help Me Out

I’m a 26 F DM who’s been running a homebrew D&D campaign for 6 years with my college friends as players. As this campaign is nearing its end (a few sessions left!), I’m planning a new one. However, there’s a big dilemma I need help with: deciding whether to include one of my players, “Emma,” in the next campaign.

Emma has been with us since the beginning, but over the last 4 years, she’s been increasingly problematic both in and out of the game. The group has come to me with concerns about her behavior, and I’ve had multiple discussions with her before, but nothing has really changed. I don’t want to hurt her feelings or ruin our friendship especially since she seems to rely on this group as her main social outlet (she dropped out of college, doesn’t have a job, struggles to socialize IRL, and has chronic pain that’s gotten worse over the years). At the same time, I know the group and I don’t want to go through another full campaign like this.

Here are some of the issues we’ve been dealing with:

Rules-lawyering: She calls me out on rules constantly and doesn’t like me adding flavor or doing “rule of cool” things as a DM. She’s also been ungrateful about homebrew items, claiming others get better ones. Romance focus: She gets upset that her character doesn’t have romance handed to her. I reward roleplay and interaction with NPCs, but she expects it without effort.

Combat issues: She takes forever during combat (10+minutes to decide on her turn), which leaves the rest of us waiting around. Attention-seeking: She makes her characters act like protagonists, pulls focus onto herself, and expects reassurance or attention (both in-game and out).

Mixing IRL and in-game: If she’s upset with someone IRL, it shows in how her character treats theirs. The rest of the group feels like I’m playing favorites by not being direct enough with her. They want this to be a unanimous decision (we’ve kicked someone out before for not contributing much), and I agree, but confrontation is really hard for me. In past discussions with Emma, I’ve softened my words to avoid hurting her feelings, which the group thinks hasn’t helped. I even asked another player to lead one conversation because I just couldn’t do it.

To make things more complicated, Emma is super excited about the new campaign even though nothing’s finalized yet, she’s already created a character with a full backstory. I feel awful about the idea of not including her when this group seems like her main connection to others. At the same time, I want this campaign to be fun and drama-free for the group and myself. I value our friendship, but I don’t know if I can handle another campaign like this. I’ve tried to address her behavior before, but nothing sticks. What would you do in my position? How do I balance preserving a friendship with keeping the group dynamic healthy? Should I let her stay and set firm boundaries, or is it time to cut her from the group? I just don't know what to do right now. Any and all advice would be helpful. :D

-A very conflicted DM