not controling the resistence

FWIW: Many smart trainers will produce resistance curves that emulates a dumb trainer (increases with speed) when not being externally controlled for resistance.  These generally simulate dumb trainers that have either fluid or magnetic resistance units.  A few will even do this when not plugged in and supplied with electrical power.

ok. I will try that.

Interesting, I always assumed it would be a straight line where the power increased linearly with speed.

No, for ex. if you train just using the app from the phone, it will show power ,to control resistence i have to increase incline or wattage, i don't want the trainer to set  power from a train, despite the gear the you have, small ring, big ring, it sets to the power ando you just have to pedal, i want to pedal to reach the power, like in road conditions.

Again, without resistance you are just going to spin empty. When you ride outside, the grip of your tires produce friction - higher friction = higher watts. Then you have the wind, weight of the bike, incline etc. This are all things you don't have on a trainer.