TikTok installing by itself brand new iPhone 15

Context: I've been using iPhone as my primary cell since the first version with "EDGE" internet came out. Such a capable device became even more capable once jailbroken and Apple got their act together with the appstore and carrier-unlocked devices, so I never again had any use for cydia or sideload sw on my personal iPhones.

I purchased the new 15 last week (factory sealed of course), as I do every 2 years. At first boot, all usual Apple apps (i.e. Clips, Keynote, Numbers, Garageband, iMovie, etc.) were pre-installed - all good so far.

The issue began when I could not get my AT&T eSIM transfered over to the new device, being repeatedly stopped with the following error message: "Unable to Transfer Phone Number. Your phone number could not be transferred to this iPhone. You can try again, or contact AT&T for assistance." Thinking it could be a software issue, I did a factory reset... just 30 minutes after getting it out of the box! Tried again to transfer the line with no luck, so in the end it was not an iOS thing. I did have to get a new QR code for a new eSIM with the carrier and all was fixed.

Still with me? Once iOS loaded, I saw that the factory-installed Apple apps were not there (this behavior is explained in other threads and is expected after factory resets), BUT HERE IS THE STRANGE PART: next to all the base apps was the TikTok app icon which, of course, I DID NOT download.

Can anyone who knows what they're talking about, please explain how that is remotely possible? I cannot get my head around it. Several Reddit threads point to App Clips and Test Flight, but again it was a fresh device. I find it extremely worrying that a Chinese company with Byte Dance's reputation can have their app loaded without user interaction on a brand-new, America-bound Apple device.