This is really complex and I can see all sorts of perspectives.
What I want to say, very very very gently (because at your stage I was beyond exhausted, overwhelmed, doubted myself at every turn, and was pretty much down to my last nerve) is that whatever you're feeling in terms of confusion, struggle and intense feelings - your children will be feeling that too. It will get easier for all of you, but for a time it's going to be hard. Access all the support you can for yourself - can people help with shopping/ cleaning/ gardening/ errands/ coming for a coffee to make you laugh for a bit? Any of that is great, and gives you precious headspace to connect with your children.
The best advice my SW gave me in those early days, was to focus on ways to give the child opportunities to express their feelings. This might be with language if they have it, or you could use pictures, books (Todd Parr's The Feelings Book is good). You can describe the feelings for them to help them process "I can see you're feeling really angry there, I wonder if you can feel that in your tummy? In your head? In your feet?" No need to get answers, just to acknowledge the feelings and that they are hard. I always used to end with "I know the feelings feel really big right now, but I'm here, and together we will get them to feel smaller".
You only get these early days once, and they are simultaneously the most exhausting-draining-demanding-emotional time - and the most precious opportunity to grow trust. Sometimes children need very different things after placement than they did in foster care, because a big regression step is normal. You are getting to know your new children, and doing your best to make the right choices for them. That's all you can do, every day. For most newly-placed children, coping with childcare is too much because it means learning to trust and attach to yet more new adults and places, which can be confusing and make it harder to build the new bonds at home. This isn't an exercise in trying to make you feel guilty (you'll feel guilty all the bloody time anyway now you're a mum!). You need to base your choice on what will be best for all of you to cope - your new children need you with them, and you also need to not go mad. That's where making sure there is real-life support for you from friends and family comes in. It's not a simple or easy path to navigate.
to you.