"EFHW" means end-fed half-wave. It is by definition a half-wavelength long, so it is not short. And it's fed at the end, so it can't be a loop, which has no ends. I wouldn't say it's a very good choice for a space-limited application.
There are loop antennas too, and any wire antenna can be bent or curved, though that may make it a very different antenna. Any wire will radiate, but the radiation pattern and feedpoint impedance may be substantially altered. That doesn't mean it won't work, it just means someone would need to build the antenna and measure it to find out, or enter the precise geometry into a modeling program.
However, in your situation, I would recommend looking at antennas designed for mobile use, rather than trying to cram a large antenna in a small space. Going this way I think you'll get more consistent performance.
For example, see the MFJ Ham Stick. Ideally you can mount it on a balcony railing similar, but if such a thing isn't available you can lay out some radials made of ordinary copper wire. There are also brackets that mount two of these antennas base-to-base, making a short dipole which requires no radials.
Of course there are many such antennas, and some are tunable, can operate on multiple bands, and so on. The Ham Stick isn't anything magic, it's a monopole antenna with some inductive loading. You can make your own such antenna by winding a coil and sticking it in the middle of a stiff wire. And if you enjoy antenna experimentation I absolutely encourage you to try it, but if you just want to get on the air you can find mobile antennas that are really cheap and don't need anything but minor tuning adjustments to get on the air.