Find an older local democrat and give him some deer meat and occasionally some new shoes that "just didn't fit right", pay him to mow the camp yard, invite him to come to camp and eat supper, maybe drink a few, and ask him to help keep an eye on the place. If you're a decent judge of character your break in problem will get significantly better. If you're not, you probably didn't make it any worse anyway.

Setting up a perimeter with flashbangs might not stop them but it would give them a good scare
Maybe even set up a few inside the entry points of the camp house

I hunted with a group of well-off Cajuns back in the late 70's in Pickens County. Several places around us had been looted when folks weren't there hunting. One time the group left for Tuscaloosa to have a good time and came back when the local thief thought they were gone for the week. The thief took a beating, and I mean a beating. This one act put a stop to the stealing in the area. Whether this was the one doing all the stealing or not, but the stealing stopped. Nothing else ever came up missing while I hunted with them.

Put radioactive stickers on random rusty containers. Or if there’s a bunch of mask wearing locals, change it to biohazard stickers.

Dig some punji pits and make sure the spikes have a fresh coat of feces on them.

Can’t stand a damn thief. I’ll leave it at that.

See my byline! I cant either.

Cell cams are almost a must have now. Unde $200 for a camera and solar panel, $120 a year for monitoring. Cheap insurance.