Hi [NAME] thank you for sharing question.  Advocate a large capacity ultrafast OS (C:) boot drive and create clone (copy) as the replacement OS (C:) boot drive. All licensed applications will not require further registration. Purchase of new SSD should come with free cloning application, or use Macrium Reflect Free, Download Macrium Reflect FREE Edition - MajorGeeks.   Keep the original 256GB OS (C:) drive in safe place as your standby SSD, as part of your disaster recovery plan. 
I'm looking to add another SSD. I'm thinking of the Samsung 980 Pro 500GB PCIe NVMe 4.0 M.2 Internal SSD (MZ-V8P500B). But I'm looking for other options and I don't even know if it's compatible?
m15 R5, which SSD?