have you tried a dummy? If she gets comfort from sucking your finger, she might sleep with a dummy?
Can you assemble the buggy in the house and push back and forth until she goes to sleep (maybe with a snooze shade over it to make it all dark and cosy) and then leave her there? I know a few friends who started off with buggy naps like this in the house, then progressed to cot naps when their baby was a few months old.
I know you're not keen on a sling, but my DS used to scream when I put him in, and would only calm down and fall asleep once i started (briskly!) walking somewhere. Although that's probably no good to you if you're not keen on walking everytime she needs a sleep.
other things that worked for my friends included one of those vibrating bouncy chairs? her DS took all his naps in that in the living room until a year old. We were quite lucky with my DS cos he used to nap ok ish in his moses basket in the front room as long as he was swaddled and had his dummy when he was your LO's age. Once he was about 10-12 weeks old we had to put him in his cot in a dark bedroom instead cos he was too easily distracted by everything. he is the same now at 13mo - sleeps well in pitch black bedroom, naps terribly out and about in the world.