Why is my iPhone not available for synching?

If your iPhone is not showing up in the Finder Sidebar, then go to Finder menu > Settings > Sidebar tab, and check the box to show CDs, DVDs, and iOS devices.

More info: Customize the Finder sidebar on Mac - Apple Support

uemit wrote:

Thanks, good to know.

But is this it? Do I have to live with the knowledge that I can't sync my iPhone ever again?

Make a detour to safe-boot, and then boot normally and try another known-good USB cable in another USB port (make sure there is no lint there -- do other USB devices work via that port?).

...and don't use any 3rd party virus apps (Avast, AVG, Bitdefender, Intego, MacAfee, Norton, Sophos, Kaspersky, ESET NOD32, Trusteer, PC Matic etc) and 3rd party "cleaning", "optimizing", "speed-up" apps (CleanMyMac, Cleaner One, MacKeeper etc). They produce obscure errors like this and are not needed (MalwareBytes and AppCleaner are exceptions but should be used manually and cautiously).

An EtreCheck report would eliminate much guesswork, so paste the complete report here using "Additional text" option, so we can examine it for possible clues:

Using EtreCheck to Troubleshoot Potential… - Apple Community

Go to Finder > Settings > Sidebar tab > Locations > make sure "CDs, DVDs and iOS Devices" is checked.

The fact that you can see your iPhone in the Photos app is a good sign.

macOS Sequoia 15.7.8 came with a separate update for Finder to improve the iPhone connection. I suspect that macOS Tahoe 26.6 has the same update. On my Mac, the Finder update prompt was hidden behind other windows. Try to minimize all windows to see if you can see this Finder update.

Otherwise, in Finder, click Finder > Settings, select the General tab, uncheck "CDs, DVDs, and iPods", reboot your Mac and check that setting back on.

uemit wrote:

Maybe I'm slowly going crazy but I do not have 'Accessories' like you do (MacOS 26.6 and iOS 26.6 here)?

And when I search the System Settings through its built-in search only 1 entry shows up but double-clicking it leads to the generic Privacy & Security landing panel without anything selected or highlighted. It behaves like a dead link.

Do you ever say what exact Mac is this...(?)

Intel is different than M-series macs

You are not going to see the same Settings there on an Intel mac even running the current 26.6

In the side bar move your mouse to the right side to reveal the hidden caret and spin it open— if that is the extent of your issue..

Connecting an iPhone is the same as it’s been for years.

Sync content between your Mac and iPhone, iPad, or iPod touch - Apple Support

Since you have a Mac laptop, you may need to allow the iPhone to connect. Check System Settings > Privacy & Security.

There is also an initial ‘trust’ prompt on the iPhone that you need to allow.

About the 'Trust This Computer' alert message on your iPhone, iPad, or iPod touch - Apple Support

uemit wrote:

I’ve done the Etre report and nothing points towards a hardware issue.

It shows a few software issue but definitely nothing physically wrong with my MBP.

I’ve just tried safe-boot and even with MacOS 26.6 the same sluggish behaviour is happening. I’m going to force restart now.

Post back here with your Report, as per > How to use the Add Text Feature When Post… - Apple Community

uemit wrote:

Maybe I'm slowly going crazy but I do not have 'Accessories' like you do (MacOS 26.6 and iOS 26.6 here)?

That option is present on M-series Mac laptop computers, but not present on Mac desktop computers. In your initial post, you stated you have an MBP, but if you have a desktop Mac or an Intel MBP, then the option will not be there.

Sounds like you may have more significant problems.

For what it's worth, connecting a phone works normally on macOS 26.6 for me, as it always has. I rarely connect my phone with a cable, so when I do so the first thing that I see is the allow accessories prompt (this is an M4 Pro MacBook Pro).

After allowing it, it shows up in the Sidebar as expected (though I do need to apply the iOS update for 26.6).