Floor systems and solar do require higher water velocities. If all you had were floor returns and no wall returns, for the floors to function properly, higher speeds will be needed or the floor returns won't pop up. The also increase head losses.

A robot, such as a Dolphin or Aquabot (not endorsing any particular brand), run for an hour or so a day, uses a lot less electricity than a pump providing the flow needed for a floor system or pool sweep like a Polaris or Legend.

I am not a big fan of in-floor systems.

If you have the Southern facing roof that solar requires and it's you have a two story or ranch style home, great. Solar will be good. If the pool gets too hot, additional run time at night will help cool it too.

Solar, when heating, does want the water to travel through the panels quickly. That doesn't always equate to a variable speed's top end. There will also be months that the solar isn't needed for heat. Running at half speed for them is usually sufficient and still saves energy compared to a single speed and often less than a two speed. Not needing the high speed for solar would mean you could run slower and longer for basic circulation with a couple of short periods at a higher speed for skimming during the day.

Scott