I think this may stem from boredom, considering it occurs when you’re not there. While a walk-in closet can be spacious, I assume there are no windows and the visuals are pretty static, so being there, alone, for multiple hours at a time with no visual, audio, or physical stimulation can be depressing and/or stressful for a rabbit. Space is great, and I’m glad to hear you provided more than a simple Xpen, but stimulation is also important. Rabbits are social creatures, and repeated periods of loneliness and this behavior are good indications that your rabbit needs a friend and/or some changes to the current situation to be happiest. Rabbits are not inherently destructive and out-to-annoy-you; they’re simply responding to their environment and their emotions. It can be really overwhelming, absolutely.

Perhaps you can rearrange stuff each day before you go, so it’s always new. Give her tunnels, move around boxes, etc.. Another idea is hiding food around so she is encouraged to forage as a wild rabbit would when they’re active. Some rabbits may benefit from having a TV on or some noise in the background to get some stimulation in the environment as well.

I would also do a mental and physical check of her to ensure she’s healthy. Rabbits can sometimes either retreat or “flare up” when something is wrong with them, either because they are instinctively hiding from predators or they are venting frustration at pain/discomfort.

How often are you gone and for how long?

Sorry to hear you are having so much trouble. Could be a lot of different things. How long ago was Remy fixed? It is possible that a hormonal surge post-surgery could be causing the extra potty accidents if she was spayed in the last month or so. This will settle down as she gets a bit older.

If she has plenty of toys and entertainment but is still being destructive I would suggest rotating her toys so they are more interesting to her. If I leave toys in my rabbits cage all the time he never plays with them because they aren’t as interesting as new toys. As a chewer, I would suggest filling a cardboard box or plastic bin with shredded paper and cardboard for her to play with. Paper tubes full of hay and other interactive toys may be more enticing.

You also mentioned that she is destructive when you leave. This may be due to her feeling like the closet space is a negative place, where she has to stay when you are gone. I would try to use treats and positive reinforcement to encourage her to play in that area even when you are home so it becomes a safe space and her home base. At the very least, an x-pen my be useful to put up around the inside perimeter of the closet to make a barrier between her and the baseboards/walls.

Good luck!