You mean you are using the itunes playlist within traktor ? Are the tracks already analyzed ? if not I’d say this is probably the culprit.
How do you mean isolated ?
If you are Tethering a phone is just as bad as using Wi-Fi/Bluetooth etc.., you should not be using unnecessary network or USB devices while you are gigging.
Isolating your laptop’s power is not going to change anything.
There are so many things that can cause dropouts that’s it’s tough to start. I’m assuming this is a Windows PC that you also use daily? If so, I really can’t ever recommend using your DJ machine as your daily computer in almost any circumstance.
If all of your latency settings are set correctly and this just randomly started becoming an issue, a reformat may be in order.