iPhone video files (.mov) seem corrupted in Premiere Pro

The videos from my iPhone (with a .mov ending) seem completely odd when importing them in Premiere Pro. In the Windows Media Player and in the Explorer Preview they are completely normal. But when I browse the Explorer in Premiere, the preview looks corrupted (as depicted in the Screenshot). What could be the reason? How can I solve this? The problem stays when creating another project.

Note: I tried to convert them to .mp4, which resolved the problem, but I couldn't find any free converter that can handle all my footage. But I couldn't find a converter that can handle all of my footage for free. If anybody happens to know a converter/a trick that can handle this, please let me know.

Otherwise, I'd prefer to solve the problem in Premiere Pro directly.

Version: 23.1.0

Platform: Windows 11, 22H2

Thank you!