Try to think about where you are likely to want to go with your baby.
We had the bebeconfort loola up, with the carrycot and adaptors so that maxi cosy car seat could fit in.
We live in London, and tbh any pram is very difficult to get on a bus, so I was either walking locally, or getting in the car.
The carrycot we had also doubles as a car seat (but we never used it that way), so weighed a ton. So if I was going out in the car just for a shortish outing, I would clip the carseat into the base and leave the carrycot bit at home. But loved having the pram for walking out the door of the house iyswim.
DS and I didn't get on with a sling personally, but used my baby bjorn loads.
After a year, we bought a Babyjogger City Mini, which is genuinely one-handed folding. If I were buying now, I would look at that with the pram attachment, although I've not seen it.
We got the base for the Maxi-Cosi and I did appreciate being able to just click the car seat in and out, so would recommend that if you can afford it.
Good luck!