Any method is adaptive by default. The documentation mentions it the other way around: there’s an explicit mention to any method that is fixed time step only.
EM- The Euler-Maruyama method. Strong Order 0.5 in the Ito sense. Has an optional argumentsplit=truefor controlling step splitting. When splitting is enabled, the stability with large diffusion eigenvalues is improved. Can handle all forms of noise, including non-diagonal, scalar, and colored noise. Fixed time step only.†
https://diffeq.sciml.ai/stable/basics/common_solver_opts/#Basic-Stepsize-Control
adaptive: Turns on adaptive timestepping for appropriate methods. Default is true.
So just use adaptive = false.