The stat caps cannot be modded, they are hard coded to '15' in the .exe.
... although you could maybe hex-edit that. Don't know if anybody has done that yet, maybe there's some 'trainer' for that.
You cannot remove the game's soft cap but you can increase it although I'm not sure about possible side effects of such absurdly high levels.
It's not tons but megatons of work, A LOT of stuff would have to get adjusted or newly created.
I've increased the 'soft cap' from 20 to 25 in my XC_Bags mod and that was already a lot of work for only 5 new levels. Even thinking about increasing it to level 150 makes me shiver ...
So if you have hardly any time to play, you will most likely have even less time to do such modifications, which might or might not work.
And you will also most likely have no time to learn modding D:OS, because modding the game is not really easy. All the required info is here in the forum though, mostly in the stickies.
My suggestion would be to better start with a cheat of level 20 or better 15 (20 in XC_Bags should be 'safe'), you will still one-hit almost everything up to very late levels where you might need two hits. (You can never breach a 'Void Aura' though or the Death Knights' 'Invulnerability' without the required spell, no matter if you're level 10, 20, 145 or 50123.)
I never had a problem with traders above level 20 but then, I never reached a level above 22 except in the XC_Bags playthrough where I made it to 23 and there it was even less of a problem because it was even below the increased soft cap).
I have no idea how far above the normal soft cap of 20 one can be before traders no longer sell anything.
Even with absurd levels, I doubt that Divinity can be finished in 'no time', combat is only one part of the game, there is a lot more where gear or level cannot make progress any faster.