How to set the ownership of a USB HDD when it is automatically mounted

I manage my music on a USB HDD.
So I want to use a Samba server to manage it from my PC without having to reconnect the HDD.
However, I am troubled by the fact that volumio automatically mounts the HDD and the owner becomes the root user.
Currently, I have to unmount it once and then mount it with the following command, but it is very troublesome.
mount /dev/sda2 /media/Volume -o uid=65534,gid=65534

I would like to know how to set the user of the HDD as above automatically.

Volumio Information

Volumio Version:2.873
Hardware: Raspberry pi zero WH
DAC:pHAT DAC

You could add an entry to /etc/fstab
Take a look at the info here automount - How to make partitions mount at startup? - Ask Ubuntu
editing fstab might break Volumio updates though, so keep a backup of the original that you can restore before doing an update.

Are you sure that the drive is mounted as root? If I look at an automounted USB stick then I see:

volumio@volumiokitchen:/mnt$ ls -la
total 3
drwxrwxrwx 1 root root 1024 May  5  2020 .
drwxrwxrwx 1 root root 1024 Jul 22  2020 ..
lrwxrwxrwx 1 root root   14 Feb 19 17:50 INTERNAL -> /data/INTERNAL
drwxrwxrwx 1 root root 1024 Feb 28 13:53 NAS
drwxrwxrwx 2 root root    3 Feb 19 17:50 UPNP
lrwxrwxrwx 1 root root    6 Feb 19 17:50 USB -> /media

volumio@volumiokitchen:/mnt$ cd /media
volumio@volumiokitchen:/media$ ls -la
total 6
drwxrwxrwx 1 root    root    1024 Feb 22 10:51 .
drwxrwxrwx 1 root    root    1024 Jul 22  2020 ..
drwxrwxrwx 2 volumio volumio 4096 Jan  1  1970 338A-1A8F

So USB is symlinked to /media with owner root.

Within /media the actual USB mount of the stick has owner volumio.

@pauljwells could well lead to conflicts with two attempts at mounting the same device.

I’m no expert on this, but I think if the fstab entry is present at boot, the HDD should mount following the rule and will not ‘hot mount’
TBH I don’t think any of this is a good idea and don’t really know why the OP wants anything but default behaviour. The Volumio drives all show up over SMB with anonymous access, it’s always been one of the features of Volumio that I liked the most.
@Kai_H Great avatar!