OP is he what you need to do as the enclosure is still way too big.
Get a 6 quarts tubs, lay 1 inch layer of aspen, get a 6 inches plastic flower pot saucer to use as an hide.
Provide a hot spot of 86/88 at the most on the hot spot and 76/78 on the cool side.
Even a dark tubs or enclosed rack the animal may still feel insecure so the smaller the tub the better.
Hides also need to be very tight hence the plastic flower pot saucer.
Aspen will also allow the animal to burry itself adding more security.
Once you have done the changes, NO HANDLING, no tube feeding, for a week, once a week as passed offer a live hopper mouse....it may fail at first given what the animal has been through but if it does no more tube feeding there are other options but you will see when you get there.
When offering leave the mouse near the tub for 30 min to an hour before feeding offering a little food and water. Then put the mouse in the enclosure and close the tub, try offering at dark. If not eaten remove after 20 min.
NO HANDLING unto the animal eats on it's own 3 times if successful.
Your setup will look like this plus the flower pot saucer
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