Do I need anything besides from a stroller that I can attach an infant car seat to in baby first months?

Ideally you wouldn't use a car seat on a stroller cos baby can only be in a car seat for 20-30 mins. The one shown encourages them to be in one way too long.

Better to have one that has different attachments (bassinet, seat and stroller)

We never used car seat attachment. It’s not recommended to keep them in the car seat for long. In the first few months no longer than 45 minutes. And actually you might find your baby HATES the car seat for awhile. I recommend getting a carrier over anything else.

Ideally you wanna get one with seat, stroller and bassinet because they’re not meant to be in a car seat for very long, I think the longest a baby should be in a car seat is for around 2 hours and that’s if you’re travelling in the car. Also sleeping in a car seat sometimes causes their head to fall forward so their airways have a higher chance of getting blocked. Plus once they get passed the newborn stage they benefit from the bassinet because lying down and being comfortable flat is one of the first steps to being able to roll. A carrier also really helps for those times baby just wants to be really close. :)

As said above, babies shouldn’t be in car seats longer than 20 mins at a time, or 2 hours total per day. Doona’s are also just very bad car seats! (And definitely don’t buy a car seat second hand)
I could give you car seat recommendations but I see you’re in the US so they’d be different. Have a look at the Facebook group Car Seats For The Littles, it’s run by CPST’s who can give you recommendations for good infant carriers

if you're tall or gonna have a tall baby skip the doona and get a nuna or a joie or an UppaBaby, graco has some more cost effective options with Similar style silhouettes but 8 months and the baby feet are usually hanging over