How to disable play time tracking?
Solution 1:
No. You cannot disable time tracking nor can you reset the time tracked as was once possible for source games.
You can create a new alternate (alt) account, purchase a second copy of the game and play on that with impunity as your friend will be none the wiser.
Solution 2:
You can disable the "time played" clock while playing in offline mode. The only real reason to do this is to play an entire game then get your money back
You buy a new single player title. Play for about an hour. Go offline and disable the tracking. You spend the next two weeks playing and finishing the title and then get a refund before the 14 days is up.
First you need to have full control of your firewall so you can block the 5 steam executables (Steam, Steamwebhelper, html5app_steam, steamerrorreporter??, streaming_client).
I say "full control" because if you are using windows firewall, you don't have full control. Every time you block something your firewall tells microsoft and if they disagree, a new rule allowing what you blocked is created and Steam is on their don't block me list.
This is easy to fix, just get "Windows Firewall Control" and stop microsoft from micromanaging your PC. You're on your own with other firewalls.
Also block the games executable/s. (there maybe 2, 32b and 64b)
Don't skip putting about an hour on the game before blocking. 1: You need to play it awhile to know "I just don't like it" and 2: DRM like denuvo need to authorize your game on first run and after any update.
Meanwhile, only login to steam using your regular browser and in 13 days, after finishing that new hot title, request your refund and get your $60 back.
After getting your refund, you can unblock steam and go get another game.
PS I've tried to contact Steam to inform them of this, so far they've just ignored me.
Solution 3:
Start steam in offline mode. This way it will no longer track your progress.
Obvious downside : You cannot player multiplayer.
However, this is the only possible way of disabling play time tracking since it contributes to steam stats and thus is a vital feature for them.