Your maniacally played games.

[loc978]

I guess add me to the pile of people with several hundred hours each in Fallout 4 (1217) and New Vegas (921). Probably as many in 3, but I'm not sure... I only have the hardcopy (I do have a full Fallout 3 playthrough in my New Vegas hours, though. Tale of Two Wastelands was an interesting time).
Say what you will about the Fallout shooter titles (and I have), they've got a lot more longevity than the old isometric ones (which I still go back to occasionally).
I also have a couple hundred in Skyrim (178 regular, 106 special edition). Not a fan of the previous TES titles.

Number one and two though... Sins of a Solar Empire: Rebellion (2698) and Supreme Commander: Forged Alliance (1310 on steam). Thousands of hours each.
SupCom is another I spent a long time with just a hard copy, though... until steam allowed a hardcopy key activation for their version. All told it might still beat out Sins, just not the steam versions.

I've got a similar lack of hours tracking in Rimworld. I rarely play the steam version anymore (actually, probably never again. I left it at 420 hours as a goof). I like a more accessible filesystem for modding... which I tend to have to manually troubleshoot a lot... in every game I listed, actually.
(final edit: on a computer with steam, looked up my hours)

[Bastobasto]

Mount & Blade easily. Got 1000 hours in it.