For a 160lb rider, that’s only somewhere in the range of 14mph sustained on flat ground. That is incredibly low for a regular cyclist. Frankly, that power is just far lower than what most people can put out. My assumption here is that Strava has very poor estimation for riders without power meters. Or your route has many stoplights and stop signs, which is difficult to account for when calculating average power.

Regular recreational cyclists can generally put out 200-250W for well over an hour depending on weight.

The question here is how hard do you ride (given by the heart rate). Do you ride at 120bpm or 160bpm? If it's 120bpm, you can probably increase the output with little training or just by accepting a higher heart rate. If it's 160bpm, something seems wrong.

I wouldn't trust strava estimates. They are (or were, I haven't used it in a while) all over the place for me.

how do you want strava estimates to be reliable? they can't take wind into account they can't take the efficiency of your bike, they can't take your shape (which influence the air resistance) into account that can't be reliable at all. 89w is nothing

Was this a leisurely pedal or were you going hard?