How can I backup my iPhone directly to my external drive?

you can't

How to back up your iPhone, iPad, and iPod touch - Apple Support

SEBGO wrote:

That’s just wrong, should be a normal feature in any devise, I have the space in an external drive, have the tools to do it and only because apple wants to push people to pay for icloud they block the option. Feels wrong

Telling us you think its wrong is pointless. We aren't Apple. This is a user to user only forum. No one from Apple is here. It has NEVER been possible to backup to a hard drive. Since you believe Apple is missing something (though it's unlikely ever going to change), feel free to share your thoughts with Apple here --> Feedback - iPhone - Apple

Keep in mind with iOS it operates in a secure enclave, is fully encrypted and this is all to protect your data. Taking your data out of the secure enclave would make your data less secure if for example, that external hard drive wound up in the hands of someone you wouldn't want to have access to your data.

it was always like that also before icloud really,

if you have a computer then you can mount the external hd to the dir where itunes store it's backups and then

backup to itunes then the backup would end on the external drive

Where are iPad and iPhone backups stored on PC or Mac? (iphonebackupextractor.com)

you can complain to apple using

Product Feedback - Apple

That’s just wrong, should be a normal feature in any devise, I have the space in an external drive, have the tools to do it and only because apple wants to push people to pay for icloud they block the option. Feels wrong

It does not cost one penny to back up your iPhone to your Mac or PC. Then, you can copy/paste the backup over to the external drive. That's one additional step, but not really a big deal. Some users claim that they are able to back up directly to the external using a "symbolic link", but I haven't tried this.

Really.... I have to pay for iCloud to do this.... It should be simple! Well I figured it out.

here's the steps:

https://apple.stackexchange.com/questions/127562/backup-iphone-to-external-drive-on-mac

But on the latest MacOS you have to jump through additional hoops to create the symbolic link from the Mac's normal backup location to your external hard drive's "Backup" folder you create:

You can grant Full Disk Access to Terminal, which allows you to create the symlink

1. Open System Preferences.
2. Go to Security & Privacy > Privacy tab.
3. Select Full Disk Access from the list on the left.
4. Click the lock icon at the bottom left to make changes, and enter your password.
5. Click the + button and add Terminal to the list.
6. Restart Terminal.

The walled garden is feeling claustrophic today!

[Edited by Moderator]

Just save your photos, videos and other large files in the external drive and delete them from your phone to save some space.