Thoughts on carrycot for lie-flat push chair

Hello! So I’m early in my buying decisions (only about 17 weeks), but trying to do some research and learn.

My husband and I have looked at and tested a couple push chairs, and we really like the Uppababy Cruz v3 because it’s lightweight, good on various terrain, and has the lie flat option. At John Lewis, the sales associate said they would still recommend to get the carrycot attachment for a newborn as it’s more cozy for a newborn because they don’t need to be strapped in.

But I’m a bit unsure as the carrycot seems like an added expense that’s only good for a few months anyway. I thought maybe I could get the carrycot used, but then I also have some reservations because it’s used for sleep and a used device could have risks.

Seeking thoughts / advice on:

1. Would you still recommend the carrycot attachment for a lie-flat push chair?

2. What are your thoughts on getting a used carrycot? Or is it just best to get one that’s new and potentially more safe?

3. Also if you have any general thoughts / reviews of the cruz v3, would love to hear.

Many thanks!