I need advice please

[flyingbeet]

I have a 6 month old. She currently co-sleeps and uses me as a dummy throughout the night. I am not content with this and want to teach her to self settle/sleep train so she is able to sleep in her cot. My only problem is that we can never stick to a schedule. This is what it is like:
7am: wake up
9.15am: nap 1
9.45am: wake up
12.15pm: nap 2

1. 45pm: wake up

4.15pm: nap 3 5.15pm: wake up 8.15pm: bedtime 8.45pm: wakes up and refuses to go to bed until 10pm.

I've tried waking her up at 6.30am in the morning some days and having bedtime at 7 but she keeps suckling my breast. Latching on and off. Getting frustrated because she can't sleep. I spend three hours laying with her until it's 10pm and she is able to fall asleep.

Sometimes I just give up and keep her up till 10pm but then I have days where I want to fix her schedule but I don't know how. I consistently put her to sleep at 7-8 pm. Making sure her last wake window is 3 hours. I tried for a week and then gave up. I want to try again and know I need to change something but I don't know what. I don't know if it will affect sleep training. Should I sleep train her first and then fix her schedule or the other way?

Honestly the best part about being off with a 6 month old is you don’t have to stick to the exact same boring schedule.
You could time naps and bedtimes to the minute and it still won’t mean your baby will sleep better unfortunately!

Are you waking her up from naps or is this all how she naturally sleeps? It seems like she is treating the 8.15 bedtime like another nap and so then isn't ready to go down again until much later. It may be the case that she would do better with a longer morning nap and a shorter 3rd nap of 30 minutes or so.
If you are currently waking her up from naps, I would experiment with allowing a longer morning nap of 1-1.5 hours and then maybe another hour one and then a short 30 minute final nap of the day. That works better for some babies. Or if she wakes naturally after a 30 minute nap 1, see if you can resettle her for another stint to extend the nap.