Wires and whips are not much good indoors these days as you have discovered. The noise level has massively increased over recent years and conventional wire aerials love it.
Loops are much better, and the self-supporting type like the Wellbrook aluminium loop can be easily mounted on a pole or tripod and rotated to further null out the local noises, but Sod's Law says that as you null one noise another will come up!
I've had a Wellbrook since about 2000, and started off with it on a tripod indoors. Even that was a huge improvement on my outdoor wires, taking the noise level down by several S-points. When I got around to mounting it at gutter height at the rear of the house there was a further drop in noise.
Sensitivity is not the problem. Most SDR's are quite sensitive and adding a heap of gain in front of them usually makes things worse due to overload. To make things worse, the RTL type of SDR tends to be short of dynamic range and you are always trying to tread the fine line between internal noise and overload. There are better SDR's out there but with the general state of the bands can make it seem unwise to spend money.
Re the general lack of signals - HF propagation is very bad at the moment and has been for several years. Amateur comms are at a low ebb due to the poor conditions and anyway there has been a drift away from analogue 'phone to digital text/data like FT8.
Utilities like aircraft are still about but a lot of maritime services have gone digital, so the delights of
'Anglesey Radio, Anglesey Radio' are things of the past.
