I've been riding a hybrid bike for my errands and short transportation within the city. However as I just learned to ride a bicycle this year I'm still a beginner and still having problems especially if there are lots of cars passing by. There are no protected bike lanes in my city and there are cases wherein I worry I might lose balance and a car or motorcycle might hit me.

So I'm thinking of getting a city bike like this Elops 120 to replace my hybrid bike since I read they are easier to balance and are more stable overall. They also have a bike rack and due to the upright position, more comfortable especially for a beginner rider like me.
However someone told me it would be better to just stick with my bike or get a mountain bike because I will outgrow a city bike after a year. Also my city is full of potholes and speedbumps that aren't comfortable with a city bike. Also there are steep inclines here that I won't be able to climb due to lower number of gears and also since it is a heavier bike overall. I also don't need to spend anything if I just stick to this bike.

All advice are appreciated.