TP is obviously even better as a product if you’re working with a coach hence why so many triathletes favour it.
Strava’s a fantastic social platform but I don’t use it for anything more than that.
If you know that you're going to be running in challenging conditions like snow that reduce your pace then use the Trail Run activity profile and set "Record VO2 Max.” to Off. That should prevent it from changing your fitness metrics.
I suspect the new training status stuff that’s been rolled out would likely be a good fit for cyclists, even those who haven’t purchased a power meter.
Generally Garmin has much better features than Strava for setting up and executing a structured training plan, then analyzing your performance. But Strava has better social features. Many endurance athletes use both platforms. It's easy to create a free tier Strava account and automatically sync activities from Garmin to show your friends.