The playtime must be done in the Main Campaign, the extra Snow or Sport campaigns do not count, that also includes the Daily, you MUST play in the main campaign to get the 10 hours achievement.
This can still be done if you have finished the game.

Play through the campaign like you normally would, once you hit 50% go to the collectibles hub found through the portals in previously completed areas, check your playtime, if its shorter than 5 hours consider playing a bit slower and trying to do silly challenges to prolong your game time and have fun while you are at it.
Once you finish the game and collected all the collectibles go back to the Collectibles room and check your playtime in the 100% locked door by hitting the projector in there. Once you know how much longer you need to play to get 10 hours, set a timer, add 5 minutes, and AFK in any level, once the timer goes off you can finish the level to get the achievement.
If you still have not gotten it, double check your playtime and repeat going AFK in a level until the

AFK in any Main story mission until you have gotten 10 hours of total playtime in the main campaign, Other campaigns and daily challenges do not count.