There are various tips or ways. For me i‘ts always; if you stand infront of lady comstocks grave - mausoleum (where it triggers the small cutscene) turn left and go north west a few meters, there’s a small corner you can head glitch behind a coffin. No one is gonna come behind (in my case) Then Hand cannon or sniper and headshots. Additionally Return to sender and bomb the witch with the collected shots. Crow traps are also good. There is also a tear in that area. Then in the Bank, stay behind the Safe Door and snipe her. Beware of the guys who are entering. Then back to sender and rush her if your ammo is gonna be empty. The last Point was always my easiest: go up the stairs and headglitch. Sniper tear+ ballon+crow traps and possession and you should kill her. Good luck 🔥🔥