The v2.x single bay My Cloud overwriting any changes you make upon startup or reboot is a well known issue. There are various discussions that can be found using the forum search feature, magnifying glass icon upper right, that discuss various methods or ways to try and get around this issue. Here is one such discussion which has links to two other discussions.
https://community.wd.com/t/add-cron-job-to-my-cloud-gen-2/187822
