Doona or carseat?

Parents who've used doona , would you recommend to get it? Me and hubs are considering to get a doona carseat stroller so that it'd be easier to travel around if we were to take public transport (especially phv) since nowadays it's kinda hard to get a cab even when booking through app. Tbh , I don't wanna spend money on something we're not going to be using for a long period 😅 what's the max age/weight for the doona that you've carried your child in? I noticed it's kinda compact and am afraid baby would feel uncomfortable if they grow bigger. Or is there any carseats that is suitable from newborn usage till they are abit older? #advicepls