Based on how Plesk is designed, it should be simple to implement. The only explanation for why it hasn't been completed yet (despite being requested for YEARS) is that Pleks developers are either arrogant or lazy.

Let's go, guys. Have it done already!!!

Ability to use multiple HDDs as long as they are formated. Move files between HDDs and choose on which HDD to store subscription files, also ability to move subscriptions between HDDs

its very important nowadays

Please help here!! : https://plesk.uservoice.com/forums/184549-feature-suggestions/suggestions/40214683-multiple-drives-compatibility

This is super important.
As @ Digital Ocean we can add multiple volumes we need the option to distribute our webspaces in a different storage, for many reasons, one, I can host some websites in volume1 and other in volume2 and take different actions with the webspaces on volume2, like I can snapshot a full drive for backups, and many more scenarios.

With many VPS hosts offering block storage as a more efficient method of increasing disk capacity (without having to increase costs by also purchasing more CPU and RAM with disk capacity), this is an absolute MUST for hosts to manage disk usage and space.

Yes, especially with affordable block storage on various VPS providers. For example another control panel allows sites to be hosted on multiple drives, for example mounted as home, home2, home3, etc.

This would be very valuable

It would be a great idea to implement an option for users to be able to choose the storage drive that is mounted on the dedicated servers. For example, if a user has 1gb storage on bay 1, then adds a second on bay 2, it would be great for Plesk to have an option to choose where to store a subscription and or customers storage location. This eliminates costs of having to upgrade to another server because of current limited storage.

Cpanel offers this, not sure why Plesk doesn't. VERY crucial feature that should be implemented asap. Please implement this.