You can run 50 to 75 watts inside your apartment with a portable antenna, a mobile rig and a power supply. I don't remember the brand and model of my antenna, so I will describe it. It is an automotive ground plane antenna of the type usually mounted through a hole in the roof. Instead of being mounted to sheet metal, it is mounted to a 90 degree angle bracket, and there are three equidistant radials pointing down at 45 degrees. The angle bracket is attached to a short piece of pipe with a u-bolt, and the pipe is attached to a small board (bookshelf) using a plumbing floor flange. The entire thing sits on a table and the tip of the antenna is just below the ceiling. You can place this portable antenna where it least interferes with your lifestyle, and put your rig and power supply where the operation is convenient. This antenna works much better than a J-pole type of antenna indoors, as it is less sensitive to SWR fluctuations due to nearby objects that detune the J-pole.
You can run as little power as needed to get into the area repeaters, or set your rig to full output for simplex contacts many miles away. Since there is no fixed connection to the building structure, there is no issue of damages and necessary repair. It can be broken down and moved easily by detaching the radials from the angle bracket, and the pipe from the floor bracket. You can store it (or disguise it when not in use) in a fishing rod case.