I use the FR245 as well. I can confirm that there is a 50 point (number of turn-by-turn directions) limit in terms of navigation, which I expect is limiting even for “regular” running and definitely insufficient for CS. I usually hit the limit somewhere between km 7 and km 11, depending on the area.
That said, I still find the navigation very useful and use it for all my runs since it’s easy enough to just look at the breadcrumb track and turn when it shows a turn (exceptions are bunched intersections with many streets going off at similar angles, especially in areas with poor gps signal). By the time the watch runs out of directions the degrees of freedom are generally reduced to the point that an obvious remaining path emerges even for complex routes. I can set the zoom level on my watch, so I’ve not had the issue described by @18945368a4555f8cccf4 .
Tracking is excellent in suburban conditions, good in urban, definitely a bit iffy in old city alleyways. It’s much better than my phone for all three.
Overall I would rate it a 7/10 for CS, probably a good contender in terms of cost/street compared to high-end watches.