Can't transfer custom ringtones and other multimedia from Windows to iPhone

Hello,

Since some time now (maybe a few months), I no longer can transfer custom ringtones and other multimedia from my Windows PC to my iPhone.

I'm using Windows 11 version 23H2, Apple Devices 1.5.0.160 (1.1280.40963.0) from the Windows Store and iPhone 13 with iOS 18.1.1. The option in "Apple Devices" to manually manage multimedia is enabled. The option for automatic cync is disabled.

I can copy the files (e.g. custom ringtones with .m4r extension) from my file manager and paste them in the "General" tab of "Apple Devices" (with my iPhone connected). Then they appear in the "Tones" section of "Apple Devices". But they do not appear on my phone in the list of ringtones. Even if I press the "Sync" button in "Apple Devices", the custom ringtones still do not appear on my phone. Actually, yesterday I managed to upload one ringtone via the same procedure, though why it happened then and it failed the other times I have no idea.

Previously, when I used iTunes for the same purpose, it worked perfectly. Unfortunately, the new versions of iTunes seem not to support the transfer of multimedia such as custom ringtones. If I could get one of those older versions of iTunes, I wouldn't mind using it, because transfer of multimedia (e.g. ringtones, music, photos, etc.) is important to me.

I tested a few external programs for Windows that clame to be able to transfer multimedia to and from an iPhone, but they seem not to be very accessible (if at all) to use with a screen reader.

Any suggestions, ideas, etc.?

Thanks in advance. 🙏