My first thought is that if the building is less that two years old, you need to get the Owners Corp (your committee) to claim and pursue this as a building defect as soon as possible.
If it’s more than two years old, you need to pursue this with the committee as the owners corp will now be responsible. Clearly, lift noise that keeps people awake is unacceptable. There are ways of reducing the noise and they needt be all that expensive. The problem will be if the lift’s supports are driilled in to the other side of your bedroom wall but even then a false wall could make a huge difference.
Apart from that, my best advice is to act now and, if necessary talk to an experienced strata lawyer ASAP.