If “homematic_HmIP_STHO_3014f711a0001f58a9930328_000ED709AED3C6_1_ACTUAL_TEMPERATURE” is too long for you, why don’t you simply use a shorter name for your item?
Another option would be, that you create your own widget for this. I guess you are going to use it multiple times. Just stick to https://community.openhab.org/t/habpanel-development-advanced-features-start-here/. You can simply create a config-item for the item you want to get the values for and access them in you code.