Guhle produced more points at 5v5 over the last two years than Matheson, and he's also outproduced other stud young Ds like Heiskanen, Sanderson, Seider, etc in their head to head season. Don't let the fact he's not used as a PP player and the fact he's deployed in some of the hardest minutes in the NHL distract you from his offensive potential.
Also, we just saw Matheson produce 67 points, can you really say Guhle has lesser tools than Matheson? He's as good, if not better of a skater, certainly faster, he's bigger, has a much better shot, etc.
I think you are a victim of the same thing a lot of Habs fans are here, that you let the stat page and the reputation of the player dictate your opinion a bit too much. What we saw in the last ~3 years from Guhle is not the potential of an offensively limited defenseman, he grew leaps and bounds from his draft year and he's blossoming into a real f***ing stud D.
Take it from a guy that hated the pick at the time, get hyped he's gonna be great.
Ultimately his offensive production is going to be limited because he's clearly never going to get his shot on the PP (If I was his agent I'd be going ham tbh.) But that doesn't take away from what he'll be able to do at 5v5.