kinda new to reddit as a whole so bear with me -

im trying to edit a bunch of pictures for a gaming wiki, the general idea is to just make the images background transparent. but some images have parts that are translucent and can see through them, im not sure how to go about that. here's a picture for reference, (the staff orb has a wall texture behind it) https://imgur.com/a/ffpndfk
i've got about 100 of these to do, and im not exactly sure what to do.

also, my current method is zooming in and using the polygonal lasso tool, is this the most efficient way? i used to play around with photoshop and i vaguely remember there being a way to just select the subject in the picture with just a click, but when i use it, and then inverse my selection and delete the background to make it transparent, it seems to feather the selection quite a bit, and i can't seem to find a way to stop the feathering, is that just how it is? or am i missing an option somewhere?
thanks!