I also own a Canyon Grail (the alloy one, so no weird handlebar) and it's pretty capable for fire roads and some singletrack. When it gets really rocky and rooty though I find myself having less fun simply because the riding experience becomes so jarring and rattly. It's also way more fun to climb on (as in you actually enjoy the climbs as opposed to just doing them to get to the downhills) compared to a mountain bike. Where I live I have to ride ~7 miles each way to get to the trails so it makes a lot of sense as my one off-road bike.

Yeah some of the gravel bike stuff really amazes me these days. I can't imagine doing some descents on anything but a fireroad with a gravel bike due to the un-slack geometry, but I've seen people bomb green downhill runs at some bike parks!

Mostly just normal gravel roads and forest paths. I have done some very light MTB trails (here in the flatter than flat Netherlands), and did some touring through the German Eifel (that was intense!) and the Belgian Ardennes.

For me it's al about having the freedom to go where I feel like going in the moment and not having to worry too much about gear. For me this bike is like the golden mean, but there are other gravel bikes with slightly more clearance or better shock absorption if you're looking to take it on slightly more intense trips.

Here's a quirky gravel-centric YouTube channel I came across a while back: https://www.youtube.com/channel/UCV9WtB_q5sJfe3Rev5PWy-Q