This one? SAMSUNG Tab S6 10.5" (T860) Bookcover Keyboard Gray-EF-DT860UJEGUJ https://www.amazon.com/dp/B07VZHQ2WF/ref=cm_sw_r_cp_apan_glt_fabc_0EEMQX3JYTS8ZR1ZP0QV?_encoding=UTF8&psc=1
Does it wake the screen when you connect it?
Perhaps your dock connector is broken? Is it a newer s6?