The braking bit sounds odd to me. Before you give up on this bike or your current setup become more confident rolling slowly to a stop. Most cyclists do this so often they don’t even think about it. When you are going fast the gyroscopic effect from your wheels makes your bike stable, but as you slow down to come to a stop you have to ‘counter steer’, ie turning the handlebars slightly in the opposite direction as your bike starts to lean and fall over, to keep the bike upright. Right before you come to a full stop take your foot of the pedal and let your toes find the ground while holding firmly on to the handlebars and squeezing both brakes. You should wind up standing over the top tube with one foot on the ground and one foot on the pedal with the bike leaned just slightly.
Try going to a grassy playground and practice rolling slowly to a stop until you can do it confidently.
here is a little YouTube video: