Never launch the game through steam as just skipping the steam launch and game launcher is so much faster, however I do have a 25,6 hours counted on steam. (Mind you, Radeon counted only the time I had my RX 570 for.)
I have 554 hours in beamng on steam but I pinned it to the task bar with the app and that broke something in steam so it stopped counting so in total I think I have over 2 thousand hours from all the nights I left it running.
Quite a few... I'm gonna be honest I sometimes left the game running overnight so I cannot say it's 100% accurate, but still. Should add that I've had the game since 2015.
A general rule of thumb on the internet is "do not make large claims without image proof." Not saying I'm doubting you though.
I have had the game since early January of 2017, and I still don't have any of the achievements yet, but I do have almost 1.5K hours.