I've been there - it's super beautiful and amazing place for hiking/trekking. I did a few runs, but I was purposefully there during my off-season. One thing is that it is EXTREMELY windy. Like, the windiest place I've ever been, consistently. It made running a big challenge, especially in Torres del Paine NP.
I did a bunch of hiking in the Bariloche region of Argentina and also near Ushuaia in Tierra del Fuego (I'm not sure if either of those are technically in Patagonia). I spent just a few days in TDP and did day hikes there. It was honestly my least favorite place as the trails were extremely crowded and really heavily regulated.
If you want some real back-woods, no one else around, self-navigating kind of experience, check out the Valdivieso Circuit near Ushuaia. Not a great running option, but amazing wilderness backpacking.