That’s more than enough wind to make an outdoor workout pretty tough!
And, the difference between 85-90 and 68 rpm cadence is quite a bit. Assuming that 68 is not just a data averaging anomaly and you’re actually pedaling that much slower outside, you’re putting a different load on your body indoors and out. Random internet quote:
Lower cadences shift emphasis to increased force production; skeletal muscles work harder and fatigue faster. In contrast, higher cadences shift stress to the cardiovascular system. At the same power output, pedaling faster reduces the average force during the pedal stroke but increases oxygen consumption to contract skeletal muscles more frequently. Cycling Cadence: Economy, Efficiency and How to Train Low and High Cadence to Ride Faster - CTS
Edit to add - not saying either cadence is right or wrong as done intentionally cadence variation is fine. But a sweet spot workout at 85-90 rpm and one at 68 are not the same type of training load so you may not be comparing apples to apples between your workouts.