This method is likely to fail. If you cannot complete it successfully, move on to the (more destructive) next step.

Utilize your choice of iOpener, heat gun, hair dryer, oven, etc. to soften the internal glue.

Attach a suction cup to the watch face and pull up while holding the watch body in place until the two separate.

Be careful not to damage the FFC (flexible flat cable) connecting to the screen after separation.