Full plate bumper bolt torque

Hey there, anyone have idea or knowledge of torque needs for the 5-6 bolts holding the bumper each side to the frame? 2019 Tacoma with full plate Relentless Offroad with tire swing out and Jerry can holder. The bumper is probably 300 lbs with the tire and full Jerry cans (2) 5 gallon cans. I’ve noticed it recently begin sagging, it pushed up in to my rear fenders. I readjusted the bumper today, wondering if anyone else has had this issue and what you did to fix it?

thanks I’m advance
Chris