This disk management software can convert MBR to GPT without losing any data. Check the table to learn how EaseUS Partition master makes MBR to GPT conversion safe and worry-free: ...

The recommended method to convert these disks is to upgrade the operating system to Windows 10 first, then perform the MBR to GPT conversion. So 2k8 sounds like a no no even for an offline conversion.

A master boot record (often shortened as MBR) is a kind of boot sector stored on a hard disk drive or other storage device that contains the necessary computer code to start the boot process.

Many high-end games, professional software, and cloud security applications now require Secure Boot and TPM 2.0 features, which are only supported when the system disk uses the GPT partition ...

Turns out by default Linux (RHEL8) is still using MBR disks and so you run into the 2TB max limit. Found that there is a command "sgdisk" that will do a live conversion to GPT without any data loss.