I was about to post the same question when I saw this post.
You can set up the heading bug, but as it shows the direction of the end point of your route, it's useless when you're following a course with multiple loops and overlapping trails. So I'm also looking for a way to see the direction of a track. I guess you could use 'use map' instead of 'follow course' in the routing settings to get turn by turn alerts, but then the route will be recalculated if you stray from the course. That's not an option for me when I want to follow the exact hiking trail.
I fully agree. Sometimes, I see (additionally to the red heading bug) also little grey arrows indicating the direction. Often, however, they are too little to be useful.
What would be useful is a line style that is directly showing the direction, or simply some more (small) grey arrows.
Especially with overlapping trails, the current solution is far from ideal.
Same issue when following a downloaded track that is a loop. I arrive at the start point and need to look on the internet in which direction the loop starts, even though this information is in the time stamp of the track. Other navigation apps show little triangles on the track to indicate the direction. This is a pretty basic feature and I am surprised that Garmin prioritizes music and payment function over navigation usability.
This Fenix 6 is a disaster of complexity and I would have gotten a Forerunner 945 if it came in small size. I predict that in 2 years I get a Chinese Smartwatch and run an app like Backcountry navigator or the Ortovox app or the Alpenvereinaktiv app. Far better tailored to navigation needs.
I came here for this same issue, also with mountain biking. I've only recently started using the navigation features of the watch, as I'm learning a few new trail networks and planning rides in advance. Lollypop loops off of other trails are incredibly frustrating to figure out if I don't memorize the direction in advance. Simple arrows on the course, like are shown in BaseCamp would be perfect. Instead I have to guess, ride a few hundred feet and see if I go off course or not. I'm a little surprised this isn't already available.