Mei Mei ~
I was dismayed to learn that you'd fallen down a stairs and suffered minor injury. No fun - but glad it was nothing requiring splints and casts.
As you know, we're all unique and there is no 'normal' for regaining control of our equilibrium following AN surgery. Vestibular exercises usually help but how much varies with each person. I don't really have any balance problems in normal activity (I walk a lot) but on the rare occasion that I stumble, I usually have a difficult time regaining my balance unless I can immediately grab something to hold on to. I've had a few minor falls in that circumstance over the past five years but was never injured. However, riding an escalator (up or down) without using the handrail is no longer a problem and stairs are relatively easy (I rarely use the handrail) so, for all intents, my balance is quite serviceable . I believe that over time, as your brain adjusts to the unilateral input, your balance will improve, even if it is never exactly what it was, pre-surgery. I also believe that the folks enjoying biking, stand-up paddle-boarding, etc are (a) motivated (b) fortunate and (c) force their other senses to help them retain their equilibrium while engaging in these balance-intensive activities. I admire them and, were I a bit younger, would probably be doing something similar. I trust that, for you, with more time and 'practice' falls will become a thing of the past.