Is it the entire Hf spectrum that is covered by s7 of noise? I only ask because sometimes it can depend on time of day/frequency .
I have been dealing with these problems for years as my location is quite frankly poor for radio. A 10 metre telescopic flagpole can quickly become a suitable compromise aerial covering several HF bands with the addition of a 4:1 or 9:1 unun ,some wire as a radiator and also counterpoise radials .
This could also be configured as an inverted L.
If some of the noise is generated from a definate source and you can pinpoint it's origin it might be worth your while calling the regulator and reporting interference to the amateur radio spectrum .
Don't lose heart operating with high rise buildings around you need not be an obstacle . I operate under these circumstances and I hold the DXCC/qrp certificate all acheived on phone SSB/AM and some FM on ten metres. I'm not certain how much garden you have available but I am certain that there must be a solution . It should be possible to operate radio from almost any location in my view.
You could use digital modes as suggested by Craig I hope that helps in some way