It’s well known among runners that treadmill running is less accurate than road or track running, especially for pacing. There are multiple theories as to why, I happen to be partial to the “lack of wind resistance” theory coupled with “lack of elevation change”.
But treadmill running doesn’t mean you can’t train at a proper pace for your level or training program. You just need to convert treadmill speed to “real” speed.
Use this chart to compensate your pace for treadmill running. It covers the gamut of elevations, so you can train as desired.
Finding something worth staring at on the treadmill is, as always, still your own problem.