>>1791290>I was thinking of going more for comfort than speedIt's worth making a further distinction. You can have a bike that is setup with a -relatively- upright riding position, but still intended to be ridden distance and with effort, like a touring bike. On that bike you still want reach so you don't get cramped up. It's really not advisable to go with an undersized frame for that but if you do then you want bars up and out.
Then there's a cruiser. Also upright, but can be good with less reach. If you actually try to put watts in up a hill or ride hard that bike will fuck your back up. But great for cruisin on. If you just want to chill you could do something retarded like pic rel
flat bars or riser bars or meme bars will decrease reach so they're going to be bad on an undersized bike you intend to actually ride. But might be just the thing on a cruiser with a lot of rise.
Bullhorns don't really have any advantage over drops. The issue with drops is most of them have a 26mm clamp and 26mm quill stems with significant rise are rare. Most riser quill stems have a 25.4 clamp. A lot of people run a quill adapter for that reason.