Yeah I tried to 100% it too but I think achievement wise I got to 71% of them and couldn't bear it any more lol.Was going to 100% Fallout 4 so i never had to go back to the game again but i got to around 95% done and kinda quit since it was so boring in the end.
Started up Rise of the tomb raider instead trying to do the same and suprisingly enough the extra game modes are kinda fun now that the main campaing and the story dlc's are done.
Thinking of picking up the newest tomb raider but i guess i should wait for dlc's and a price drop so now i have no idea what to play once i am done in a day or 3.
Did you mean see all the major content or get all the achievements?