In addition to Seekforever's comments above, a basic file copy of your Windows partition would also create significant havoc within the Windows folder, which uses some file system tricks in order to allow the same file to appear in multiple locations without multiple copies actually existing on the disk. A normal file copy would result in multiple unique copies of such files being created on the destination, which will take up more space and probably break things that are set to assume that updating that file in one location will cause the other "reference" to that same file in other location(s) to also be updated.
If you really want to move your entire environment over to another drive, the proper solution is to clone your source drive to your destination drive, then remove your source drive at least temporarily to make sure your PC boots from the new drive correctly. Make sure you clone the entire drive, including all partitions, not just the C partition. If the system doesn't boot from the new drive after the clone, boot your PC from your Reflect Rescue Media and run Fix Boot Problems (so obviously make sure your Rescue Media works before you try this). At that point, the Windows partition on your 1TB drive will become your C drive, because Windows automatically assigns C to the Windows partition it booted from. And then you could wipe your old drive and repartition it as you like.
However, as Seekforever already said, if you would be cloning from an SSD onto a mechanical drive, you will take a major performance hit. And if your current M.2 SSD is an M.2 NVMe SSD as opposed to an M.2 SATA SSD, then you would be taking a major performance hit even if the 1TB drive was a SATA SSD, because NVMe is much faster than SATA. If you're contemplating this migration for storage consumption reasons, you might be better served by simply migrating non-application data to your 1TB drive manually, or uninstalling applications and reinstalling them to your D drive. Applications almost never work properly if you simply copy/paste the folder over to another drive.
The Samsung Data Migration Tool is essentially a very simple cloning utility. Reflect can do everything that that tool can, although if the Data Migration Tool's capabilities meet your needs, you might find that it's somewhat easier to use. I believe it automatically shrinks or expands the Windows partition as needed based on the destination capacity, whereas Reflect does not automatically expand any partitions to fill additional available space and depending on the partition layout of your disk won't necessarily shrink the Windows partition either. But that can be achieved according to Steps 4 and 5 of this KB article
about how to clone a disk.