I think that possibly you do not understand gearing/leverage.

Can you pick up 150 lbs? No? How about 50 lbs? If yes to the second but not the first, try lifting 150 lbs by a straight rope over a single pulley, then try it with a pulley block giving a 3 to 1 advantage.

Put another way, do you normally "Mash?' That is, pedal up hills at 30-50 revolutions per minute? Yes? Now force yourself to try it at 90rpm. Even if you can do it at 30-50, you will find that the wear at 90 is less on your knees. You might be able to do the lower rpm now, but when you get 20 years down the road, your knees will thank you.

Learning to spin requires some learning, it is worth it.