Connect to a physical device

Almost all performance debugging for Flutter applications
should be conducted on a physical Android or iOS device,
with your Flutter application running in profile mode.
Using debug mode, or running apps on simulators
or emulators, is generally not indicative of the final
behavior of release mode builds.
You should consider checking performance
on the slowest device that your users might reasonably use.

Why you should run on a real device:

Simulators and emulators don’t use the same hardware, so their
performance characteristics are different—some operations are
faster on simulators than real devices, and some are slower.

Debug mode enables additional checks (such as asserts) that don’t run
in profile or release builds, and these checks can be expensive.