Amen to that! We have 2 kitties & the thoughts of them getting run over,
abused, etc., well, I won't go thru that.  I love them & I can't imagine my
life without them.  The simple fact that there is just too much risk
letting them roam outside makes the obvious choice as a pet parent, to keep
them inside.

I keep my sliding door open, but the screen door closed. I put a bird feeder
on the balcony and it keeps him entertained all day. Your heart is in the
right place, but by letting the kitty out, the possibilities of doom are
endless. Hope this helps.

Maybe you can secure your balcony using poles and netting the entire
area? Alternatively, and a better way, which is what we did in our
balcony, was we used steel ropes and a net. You'll have to do a bit of
drilling (don't know if you're allowed to do this on your balcony) to
secure some heavy duty hooks on the ceiling. You'd use the steel rope
and loop it through the net and also use fencing accessories to
tighten the ropes. It wasn't a lot of work and the balcony doesn't
look bad with the net. You will have to net all the way up, though.
This won't work, ofcourse, if you have the top floor and therefore no
ceiling above your balcony. Our balcony with the steel ropes and net
is very secure and our NFO's can't jump out. They really enjoy being
out in the balcony during winter and summer and we've even left the
balcony door open while we're out during the day. Hope this makes
sense, and if it does, hope it's of some use. Good luck!