Temporarily remove multirest from part in write mode

Only by turning them off for that layout within Layout Options. See Hiding/Showing multi-bar rests

Note that
a. If you’re inputting from the caret, Cmd/Ctrl-Right will advance the caret by a bar at a time, including through multi-bar rests. You don’t necessarily need to disable multi-bar rests in order to enter notes within them. They will split as soon as you input some notes, of course.
b. Any enharmonic respelling you do in part layouts will not be transferred to the score (and can’t currently be automatically propagated to the score). Depending on the type of music you’re handling, and whether you’re using a MIDI keyboard or not, it may be sensible to work with a separate full score layout with only one assigned player.