This article explains whether the host auto-start setting in standalone ESXi is related to the transition to maintenance mode.
Standalone ESXi
The auto-start setting of a standalone ESXi host does not affect the transition to maintenance mode.
For information on setting up ESXi auto-start, please refer to the following document.
Change Autostart Configuration in the VMware Host Client
japanese KB:スタンドアロンESXiにおけるホスト自動起動設定とメンテナンスモードの移行について