Have look in your area to see if they have a sling library, they will hire slings and carriers and have a range for you to try. We have a ergo 360 with newborn insert that we got second hand.
Just to hop back on based on the above comment, my sister in law just got an ergo 360 with the newborn insert and really loves it!
I used the Baby Bjorn Mini with my son and found it so handy and supportive. Bought it off facebook marketplace
I found a sling more supportive for a newborn as opposed to our carrier. We then started using a baby bjorn and a Nuby carrier as she got to about 3 months!