I have sympathy for your problem. I was in a similar situation back in the early 1990's when I was renting an apartment to live in during the week while I was away from home on a job. Unfortunately, there is no simple solution, but here are some things I tried:
I had an attic opening in a closet so I put a metal chair up there with a 2 meter magnet mount antenna on it. Worked fine on voice and packet, but the limitations are obvious. No way would I have been able to run an HF antenna up there in the attic.
I tried several indoor HF antennas. A zig-zag of wire on the bedroom ceiling with bulletin board tacks. Worked sorta...
My most spectacular indoor antenna was a helical dipole wound on two 8 foot pieces of 4 inch sewer pipe. I used #14 copper wire for the windings. Hung the monstrosity up on the ceiling using screw hooks. I could get it to load 80-10 meters with a good tuner and alligator clips to vary the attachment points along the antenna (I used ladder line). I could actually run a Kilowatt into this thing but it would set off the smoke detectors every time I keyed up

...not to mention it would "corona" in the dark on some frequencies!

(I am not making this up!) I gave up on this one because I figured that qrp only was just too tedious...Your mileage may vary...
Finally, one night I noticed that the building rain gutter (aluminum!) was split into two equal lengths just above my front window. It was about a 40 meter dipole overall in length. So I ran a couple of pieces of enameled magnet wire out the window and attached them to the gutter with sheet metal screws. VOILA! I could close the window and the whole thing was nearly invisible. Of course, I did the installation under the cover of darkness one night...
Now, this was a REAL antenna, and it worked well. I could run several hundred watts into it using a tuner on 80-10 meters. HOWEVER, one night when in QSO with my Elmer back home (running about 300 or so watts) I heard a loud knock on my door and when I opened, there was one of my neighbors asking if I knew of anyone running a "big CB" around in the neighborhood (he had noticed my outbacker HF antenna mounted on my pickup truck). Seems as if someone was wiping out his TV and Phone service. Well, we lived by a major highway, so I stammered that it might be one of the 18 wheelers passing by...
I abandoned that setup as well after that incident...soon after, I found a house out in the country to rent where I could put up a real dipole.
If I had it to do over again today, I would opt for a rig that could be remotely controlled by another rig (such as a Kenwood TS 2000) installed in my vehicle and operated remotely. Good HF antennas are not difficult to come by for mobile use and you could even use a trailer hitch mount or some such that you could remove when needed. OR, you could use a remote base operated from a laptop. I have couple of friends that use just such a setup with great success. Of course, you have to have either a friend with a remote base location to use or arrange to have a facility where you could install a remote base...
Don't get discouraged, you will find a viable solution if you keep turning over possibilities. Actually, I had a lot of fun trying different things in that apartment, so it was a great learning experience.
Dave, WO4V