It is hard to diagnose an erratic buzzing noise remotely, but it is certainly not a good sign for your PSU. Fortunately, your Aurora R11 PSU is ATX format, so replacement should be simple. If you choose to replace your PSU consider a fully modular unit that is less than 150mm long. This is a list of 1000 watt PSUs that meet the aforementioned criteria pcpartpicker 
I've had this PC for 2 years (1 year warranty expired September 2021. DELL-Admin) but only started to hear this buzzing in the last 2 weeks or so. It only happens as soon as I start playing games and the fan starts spinning for the power supply. It happens every time now however that weird buzzing noise is random and erratic, sometimes I would get a constant buzz and then stop for a few seconds or a few buzzes and stop and the repeats. If it only happens when the fan starts, is the power supply fan faulty, and can it be replaced or do i need to replace the whole power supply? I have the 1000W power supply: D1000EGM-00 Dell 0WTGN Cheers
Aurora R11, buzzing sounds from power supply