Do any one thing - Red book or class notes of Lukmaan/orient ias. Class notes will take less time, will have recent examples and cover the most important things in simpler language. I personally haven't gone through Red book so can't comment on it.
Meanwhile keep looking at the pyq's as well as test papers - you can do case studies from test papers because they'd cover the most important issues.
Remember answer writing is the key in ethics there is only so much in theory that you can do.
Hope this helps.

VISION IAS MAINS 365 SOCIAL_ISSUES 2020 final.pdf



