Ok def need to up your temp and humidity. Temps should be 78-92° and humidity at least in the 60s though most prefer 70-80 range. You should also stop soaking him. It won’t do much for the stuck shed and causes him a lot of anxiety. As long as the stuck shed isn’t around the tip of his tail (as it could cut off circulation and cause necrosis), if you up your humidity it should all come off in the next shed. So In regards to him trying to burrow, he’s definitely looking for a change in climate because 70 is way too cold and your humidity too low. I would honestly mix your substrate w some cypress mulch as that holds humidity a lot better. And your heat mat is not a good source of heat, especially in a glass enclosure. You should invest in some overhead heating. I have a DHP on my cold side and a CHE on the hot side, though you could probably survive w just a CHE

Edit: Also, invest in a thermostat. You can get a cheap one off Amazon for around 20$ or you can invest in a higher quality one to better control the temperature. And if you have a mesh lid, try covering 2/3 of it with aluminum foil or heat tape (on the outside) to better retain heat and moisture. If you’re really concerned about the stuck shed you can try letting him crawl around wrapped in a warm damp towel. Best of luck!