"Candidates would need to have strong experience in Python and machine learning (e.g. SKLearn, TensorFlow, PyTorch)"

Right there you are already toast at that salary range. Its not high enough to get someone to move for much less take an in office job for. Thats going to be the challenge. Anyone with "strong experience in Python and machine learning" is going to have no problem finding a job close to or even above that range for a WFH job. Throw in desired cyber security experience and I know people getting $200k+ with just 1-2 years of cyber security alone and no coding ability. I think you are going to have to be stuck in the same boat as everyone else is looking for technically skilled talent, find someone in house that is motivated and start teaching them.