A:AnswerI bought this case from Amazon "Fintie Case for Samsung Galaxy Tab S6 Lite 10.4'' 2020 Model SM-P610" and it worked perfectly, turning the screen on and off without me having to do anything. I believe that some cases have that capability and others do not.
A:AnswerI haven't tried the HDMI route but if you have a Chromecast or a streaming device with this function it works very well and you can walk around with your tablet in hand while giving the presentation. You can also use the button of the included pen as a remote to switch to the next slide for instance...
A:AnswerIt has the ability to expand the storage but it's important to know that it's for images and data only you can't transfer apps to your SD card.
A:AnswerThe version of the 6s lite that you posted this question for is wifi capable only. It is not 4g/5g enabled so it can not work on a cell network. Therefore, being unlocked or not isn't applicable.