@Kira4 oh hen, where to start with this one.
Firstly, I'm sorry it's hurting you to see your DDs relationship with your exes gf. I myself was a stepmum for many years and my dsc preferred being with me to their dm, not because I was shiny and new, but because those "silly" dances, and photographs were all down to me to do. The parents didn't. Nor did they do anything child focused. Everything children enjoy, outdoors, exploring, daft humour, experiences with food, places, all these things neither parent cared for. They weren't interested in schooling or the basics either, but if they'd been a different kind of person, maybe they'd have cared only about education and extra curricular activities? Either way, everything fell on me and my stepkids saw from around aged 10 who was showing up, who wasn't.
Shes 11, when you're ferrying her somewhere have a cancel of plans, have a boot full of a picnic and favourite food/snacks and you take her on a spontaneous day out, just you both. Take selfies, get her to show you a tiktok trend. Also buy a manicure set, do her nails, it's a close bond thing to do, without forcing physical affection on to her.
You say she's being a stranger these days? My ex feels like that about our shared dc.
He couldn't tell you his favourite film/show/friends names/music he likes/ what colour his room is. Couldn't even tell you what subjects he's doing in college.
Who is your daughters favourite youtuber/tiktoker? What's her favourite show/film? What music does she like? Find out her interests.
I'm curious how gf has overstepped? What's happened to make you say that?
My concern wouldn't be I'm being pushed out although I'd obviously be devastated, but moreso I would worry what if ex and gf split up, then what? She shouldn't be doing the heavy lifting for your parenting, in case it's not a long term thing.
It's new to them both, having a stepmum type and being one, right now they're making friends and having fun but at some point ex will have to be the bad guy and then what? That could be an awful situation.
You need to talk to your dd, spend time with her regardless of her wants, just keep trying, even if you pop over with a few nice things for her. During the pandemic I made up boxes for my pals, with treats and self care things, reed diffusers and face mask stuff, those kind of things. Would you do a kid version for her? Hot chocs/sweets/bath bombs? That kind of thing, just show her you do think of her.
Don't send her to a boarding school to salvage your relationship, she'd probably hate you.
When we have children they're ours to cherish and protect, but we don't own them, they're not ours to do with as we please, if you send her to a boarding school you're doing it for you, I think after the replies you must realise that.
If you want a relationship with her, try harder, even if it doesn't happen, you've tried, but don't make her miserable out of jealousy.
When my ex and I broke up, for years his dc chose to live with me, they just preferred being with an adult who would make effort for them. But I wasn't their parent, they needed a parent and I wish for their sakes, a parent had have shown up. They now barely keep in touch with their parents. Mum barely ever, dad when they're skint. Nothing of substance.
Even if you have to do things that feel uncomfortable to you, such as activities you're not thrilled to do, let your dd see the effort.
Dont fuck her life up with boarding school when she's settled. It would be hideously cruel.