Even in a real aircraft there is absolutely no need for a ‘reset’ button for trim. Most aircraft will have a mark on the trim wheel to indicate the normal takeoff position. This insures that you don’t encounter an uncontrollable pitch condition on takeoff. Other than that, there is no ‘center’ position. Stable trim setting will be different for every flight attitude, fuel load, center of gravity, etc.
As was mentioned before, don’t overthink it. Trim is not some magical control. Its only purpose is to reduce the amount of intervention required by the pilot to maintain a chosen airspeed/attitude. Learning to fly is not as easy as clicking an icon and grabbing a joystick. Understanding what is happening is more important that knowing how to do it.
Every aircraft has a happy airspeed that will allow stable, 0 trim straight level flight, with a centered CG. Generally, the faster you go the more nose down trim required and the slower you go the more nose up trim required. This is very simplified, but also fundamental. By using the operating handbook you can find a particular aircraft’s optimal power setting for cruise/climb. Some trim will always be required as the CG, aircraft weight, density altitude and mixture setting (normally aspirated engines) all have an effect. Wings level is also permanently adjusted, using bendable trim tabs on the ailerons and rudder, to a specific airspeed.
This all translates into a stable aircraft only at specific airspeeds. The proper method of achieving stable flight is to first set the desired power setting followed by using the controls, not trim, to put the aircraft in the desired attitude to achieve level flight, climb or descent. Once the airspeed begins to stabilize in the desired attitude use trim to remove the pressure on the controls required to hold the attitude. Very minor adjustments to trim and power may be required to hold the target speed and climb, descent rate or level flight.
Dispell the myths
Wind will have no effect on the process although may give the impression of instability in the event you encounter turbulence but a trimmed aircraft will always try to re-stabilize at the chosen attitude and airspeed.
Except in cases where the aircraft has transitioned into the “Slow Flight” envelope, attitude always controls altitude and power always controls speed. The argument is age old among instructors but is based on which should come first when changing attitude. Power/Attitude or Attitude/Power is a matter of preference as some believe one is smoother than the other. Both are acceptable means of control.
Learn the skills
Nailing a given airspeed for the chosen attitude or holding a specific rate of climb/descent at a chosen airspeed takes practice and an attention to detail. One method of getting it right is to get the aircraft trimmed for level flight at the recommended cruise power setting. Once stable, pull off 100 RPM. DO NOT touch the trim. The aircraft will want to maintain the same airspeed and so will begin to descend. Note the rate of descent. Pull off another 100 RPM. Again note the rate of descent. With practice, you will know exactly how much to reduce throttle to achieve a given rate, for THAT aircraft.
The next exercise is rate of climb. Most GA aircraft always climb at full power. this is where the handbook comes in again. Find the Best Rate of Climb (Vy) speed and Best Angle of Climb (Vx) speed. Vy is the greatest gain in altitude over a given period of time. Vx is the greatest gain in altitude over a given distance. Use Vx on takeoff to ensure clearance over any obstacles then accelerate to Vy to continue climbing to cruise altitude. Airliners or any aircraft with extreme power to weight ratios will require reducing power to prevent overspeed even in moderate climbs.
All of the above will require putting the aircraft in a desired attitude and then trim to reduce the control input required to stay there. Practice, Practice, Practice. Soon you will be flying by the numbers too.