Today I am trying to find some domain for my next project. but max. domains with high search is already registered and max. is parked domains

BTW Leave it and please help me to understand... please

I found a good keyword which have 100k search everymonth and suppose keyword is xxx
then i go to godaddy and check that all var of this xxx domain is already registered {.com, .net and .org}

Then i think to put word s at the end of my keyword xxxs {same like man and mans }and then all tld is availble.

So my question is that am i will get same serp juice for both domains because google adword keyword show 100k search volume for xxx keyword and less then 1k for xxxs.com

Please suggest me...