I've also got the love to dream bags in "cold" which is for room temp under 16. We live in a very old house and the temperature drops fast at night so I feel like this will give me peace of mind. For daytime sleeping when the house is warmer I will just use a blanket with different layers of clothes so she's not too hot. I have some hand me down sleep bags that are a lighter tog but I think they are a bit big to be safe for a newborn.
We’ve got a Love to Dream Swaddlebag in ‘cold’ (<16’) and ‘cool’ (16-20’). We used these with our first, born January and really rated them. They come with a little guide regarding what to wear underneath. I would also 2nd Purflo sleeping things though. We didn’t have any of the swaddles but used some of the sleep bags with sleeves when our girl got a bit bigger and they were really good quality and cosy x