Can I recover my photos after installing Linux alongside BitLocker?

Don't format it. Recovery software is not a reliable way around BitLocker, and formatting or continuing to use the drive can make the data harder or impossible to recover. NVMe is a type of SSD, so deleted data may also be difficult to recover after the drive processes it.

Stop writing to the drive for now. Don't run repair tools like chkdsk either. The best next step is to find a way to unlock the existing partition and copy the photos to another drive.

Windows asking for a recovery key doesn't necessarily mean the files are gone. Check the Microsoft account associated with that Windows installation for saved BitLocker recovery keys. Since the laptop came from a relative, it's also worth asking them to check any accounts or records they might have used for it.

Match the recovery key ID shown on the Windows recovery screen to the saved key. If you can unlock Windows, copy the photos and videos to a separate drive before changing partitions or formatting anything.

If you find the recovery key, you don't necessarily have to boot the old Windows installation to get the files. You can use Linux tools that support BitLocker to unlock the partition, mount it read-only and copy the files to a separate drive.

Be careful to identify the Windows partition and the destination correctly. Read-only access is the safer choice while you're trying to preserve the data.

Without the recovery key or another way to unlock the encrypted volume, ordinary file recovery software won't decrypt your photos. If the files are valuable enough, consider a data recovery specialist before making more changes, but don't assume they can bypass the encryption either.