My MTB has a top-cap type mount, so it’s inline with the steerer, My Gravel bike has an K-edge offset spacer type mount that puts it inline with the stem a little forward of the steerer, all my other (road) bikes have out-front type mounts that put it a couple of inches in front of the bars inline with the stem…
IMO The MTB and Gravel mounting positions suit a dinkier device better (Edge 25) the out-front mounts better suit a full-sized unit like a 530/830, on top of the stem/steerer is perhaps less likely to be whacked in a crash than out-front but still potentially prone if the bike is tumbling down a rock strewn trail, inboard, behind the bars, next to the stem as CFH’s pic illustrates above should be a reasonably safe position but I’m odd perhaps in preferring it to be on the centreline of the bike rather than off to one side…
I guess if you really wanted to protect it you’d put it on the Top tube, just behind the stem, but then it would barely be viewable…