From my experience, the carry cot was the lie flat option only available for a newborn. We did get a cybex recline car seat which is nearly flat but not quite. So we ended up getting the carrycot too but for us it was an utter waste of money and space. Firstly, it didn't have seat belts so when getting on and off the bus, baby would slide 🫠 not sure if this is helpful but I think if you're gonna use public transport when LO is quite young, you'll want seatbelts and that's usually with a car seat. I personally haven't seen a carry got with any. Good luck 🤞
When I had a 1-2-1 travel system consultation they did mention that fully recliners are not as supportive for newborns as they don’t have the necessary padding like carry cots but now some carry cots fold down flat to help save on space so it’s really up to you. Also some carry cots are suitable for overnight sleep so they can double as a Moses basket for up to 6 months so you get two sleeping equipment for the price of one
A carrycot lays completely flat and offers more protection from the outside world, and it keeps the baby warmer in winter months - less concern for spring/summer babies. But they are bulkier, and I’m not a fan of the 6-month shelf life either. I attended a maternity sales appointment at John Lewis and checked out popular brands like - Nuna, Bugaboo, iCandy, Babyzen etc. Most of the styles I looked at claimed they were suitable from birth. I liked the portable features of the Babyzen yoyo, but Bugaboo seemed more practical for my needs. However, I’m not a fan of the Bugaboo Bee atheistic, and the Fox, whilst better, was too heavy and bulky. Same with the other brands. After some research, I bought the Microlite GetGo, which I believe is a good halfway house between the bee and the fox. It has all the same features, plus all the necessary accessories included for a fraction of the price. I went with the carrycot based on my own needs, but can use it from birth without.
Lots of baby stuff has a life span of 6 months or less unfortunately so I wouldn’t worry too much about that. I’m in a first floor flat so carrying up and down stairs was a hassle but baby napped really well in the carry cot and I felt he was really well protected and cosy.
We bought a carry cot but honestly only used it once or twice, we used a baby carrier which was more convenient, we used to live on the 2nd floor.
By my understanding aslong as it is suitable from Birth then you should be fine. Try to see in person if you can, one 'full recline' we bought wasn't totally flat....