DS was a bit bigger when DD came along, but it was a similar struggle. I had DD in the cot for about 10 weeks. It was just easier. I didn't trust ex, so couldn't sleep deeply with her in the bed & I often had DS in my bed too. So didn't want him kicking her. Her & DS were always in their bed next to mine til the first feed. Then they slept in with me.

I used to sit with DS til he crashed out. But he was pretty easy. I still have to sit with him & he still comes into my bed almost every night, but he sleeps.

DD is harder. She sounds similar to your DD. We go to bed at 8pm every night. All of us. I turn every light in the house off at this time. That way its boring because they can't see anything. DD will still get up & wander around, but I just wait for her to come back.
I lay in her bed, quietly. She will carry on & jump around & play. I just keep laying her down & telling her to close her eyes. Eventually she does settle, but it can take an hour or so.

It will get better. If you start one routine, stick to it. Don't do it for a few weeks & try something new. Stick to that one for a few months at least. When you have the baby, you can feed her while sitting in the room with DD. You can hand her over to DP too. It won't be as bad as you think it'll be. And there's nothing wrong with having 2 babies in your bed. I've done it. I'm still doing it, I just don't have a partner on the other side.

You'll learn that whatever works, works. If they're in your bed for the next 5 years, then so be it. There's nothing wrong with that.