Sounds Good. I use a 500GB NVMe for my C drive, I should have purchased a 1TB.
I use a 2TB spinning Sata drive for backups because I already had it. Using a NVMe drive to store backups will definitely be fast, however, you may find the need for more space as time goes on especially if you do weekly incremental or differential backups. I prefer differential backups after the initial full.
Have a great weekend