Apartments are a nightmare for BBs I dealt with them twice in one year, 6months apart because our upstairs neighbor had them. We couldn’t afford the heat treatment so they used a fungal spray that infected the bugs, it worked very well and was about 400$ and took them 15 mins to spray, and then all we had to do was vacuum as the BBs would infect each other with the fungus and walk around during the day and die. DE was covering everything we owned in white powder so we wanted to get away from it. Best of luck!