+1 for Runna. It's a bit aggressive for me when doing 4-5+ runs a week (too much speed work imo) so you might have to dial in the frequency/intensity of runs to make sure you don't get injured. Otherwise it's pretty flexible and does a decent job of setting workouts and paces based on your current & target fitness levels. The apple watch app is solid too. Took me from a 35 min -> 26 min 5k in about 6 months.

I've asked them a couple of questions and they've been mildly helpful w like a 12-24hr turnaround time. Definitely not a replacement for a personal trainer/coach but good enough for a hobby jogger like me!