Floaty quad feel is a common issue many newbies including myself might experience. There are couple of reasons:

1. Not having real quad flying experience so it's hard to compare with the simulation.
   
2. Too high graphics settings that a computer can't process resulting in micro lags causing floaty feel.
   
3. Fisheye/lens effect might add to floaty feel, try minimizing it or turning it off.
   
4. Not understanding the scale, size, distances without reference objects: if you go too high and cut throttle you will fall and it will take some time, but since there are no objects to judge the speed of fall it will feel like you are floating or even suspended. Same is true when going up. Try flying close to objects. Try hover very close to a tree, light pole, or a house and cut throttle so that you can see it as you fall. Does it feel floaty? Try flying inside of a building. Does it feel floaty?
   
5. Certain quads are relatively lightweight and powerful so they can easily gain altitude and speed especially without fine throttle control and management. So racing quads presets usually might give that floaty feel. Also don't forget about dynamic idle: motors don't stop completely when you cut throttle, only when you disarm.
   
6. If you change default physics that might also add to floaty feel.
   
7. Often times 'floaty' is just a subjective perception thing. I believe that even factors like FOV, screen resolution, camera angle, and motor sounds could influence it.
   
8. Also don't forget that it's just a simulation and it's not perfect :)

The more you fly in sim(s) the more familiar you'll get with the flight feel and quads will feel less floaty.

The reason you don't have floaty feel in one simulator and have it in another is probably because you spent more time in one sim and got more familiar with its physics. Also your graphics settings in it might provide better performance and overall be less hardware demanding so try lowering graphics settings in a 'floaty sim' so that you get at least stable 75fps. Additionally your 'not floaty' sim quad model might be quite different from the ones that feels floaty in a different sim, also different maps and the way you fly around them can be a factor here. Try setting same camera angle, screen resolution, field of view (FOV), even rates. Try flying in same conditions in both sims, for example fly inside of a building about same size, try orbiting around trees, throw some simple split-S and loops around similar objects and compare it. By the way, when I switch sims even though I don't feel floatiness I feel the difference and need some time to adjust.

• My first advice would be just to fly more often and try flying proximity, not just hover in the sky. The more you fly the more familiar you'll get with a sim physics and floaty feel will go away after some time.
  
• Try different heavier and or less powerful quad if possible. Might decrease the quad power by adjusting props size, battery, motors kv if there are such options.
  
• Additionally try increasing gravity and mass a little bit, also can play with air friction and drag if there is such possibility.
  
• Also you might have a bit sensitive throttle. Try using expo if possible and/or throttle limit.

Enjoy the flow.