I ran high school cross country in the mid-1970s, and our entire varsity, runners 1 through 7, ran sub 6:00 pace or better in our races.
(Races were 2.5 miles back in the day, at least in my neck of the woods in upstate NY, so we're talking sub-15:00 for our slowest guy. I know whereof I speak, because I was our slowest guy and I broke 15:00 in my first race ever. I can assure you that our other guys were doing better to much better than that.)
So even our slowest guys were about as fast as you, or close. We did a lot of 440 yard intervals on the track, plus the usual group runs at various paces. I don't remember that our group runs were timed closely; we just kind of ran how we felt is how I remember it.
What we did seemed to work OK. Maybe we did too many 440 intervals, but I wouldn't have wanted us to do none at all. I don't think it's a good idea to run races at 5K or shorter without some interval training. You want to practice hammering repeat laps at sub-70 seconds and getting tired, so race pace doesn't feel too fast.
My two cents.