It’s ~25kg for a 2.5kw/9000 btu condenser I just looked at, but yeah, if there’s no balcony/fire escape, and you’re well off the ground, you might need some rappelling gear, and you might want a pro. No idea about whatever heavy bureaucracy you live under, that’s a human imposed rather than fundamental challenge. Pipe routing isn’t a big deal, the copper lines are very flexible, just need to be careful not to kink them - give the bends a good radius. And to answer your unstated objections, you will need some tools you almost certainly don’t have lying around. Mostly, though, you need an attitude of being able to do stuff, and getting it done.

Or you can get a portable or window unit. Midea makes some really nice window units now. Might need hung windows, though, not sure whether it’s possible to make them work with casement windows. It takes a little space, but that doesn’t seem like a huge deal?

Or do nothing and just deal with it.