This may be Vegas specific, but a year or so after the shooting, I had stayed at the Mandalay Bay and the tv wasn't working, so a really nice repair guy came upstairs to get it working (it was March Madness and downstairs was insane).
In any event, he told me that after the shooting, their staff were requested to go into each occupied room at least once a day. You can play the "DND/deadbolt" card all you want, they're going to want to see the room. The Wynn went a step further and started putting luggage through a metal detector.
I have no idea whether they still do this, especially post covid, but from my perspective, you're really risking discovery if you don't time it right. Also (and I appreciate this might come off as insensitive to those in pain), please don't do this to a poor cleaner. Either do it in the bathroom (with a note to call the police to buy more time) or another kind of warning before they step into the main room (ie a note on the wall) and at least leave them a substantial tip because they're the ones who will be cleaning up after you.
OP I don't know your circumstances, but I know you're in pain and conflicted about still being here. But with that said, you never know, this might be a good thing and there is likely a reason why you're still here. A lot of things had to go right to keep you around and the stars aligned.
As for your job, talk to your boss. Keep the details light, but explain you need to take time off either via your vacation days or short term "disability". Unless you absolutely hate your job and you're hell bent on trying again, keep communication lines open. Even if you don't go back, it's one bridge unburned.