I don’t run all that much so I don’t have a lot to compare to! I would definitely go with your experience over mine in terms of accuracy. When I run, I also have strava going to track pace.
I’ve had several hr straps polar, sunnto, garmin and the wahoo tickr has been the best so far. As for the added features of the tickr x most of these should be available on your Garmin watch already like run cadence ect but I could be wrong