Technically drives in Basic mode or Jbod should be readable when connected via USB docking station.
If you want an SSD as a primary drive where OS and apps live, you need to reset the entire NAS.
If you buy another NAS, you can set it up with SSD as the main drive and add additional drives where you copy your data to from the old NAS. You can not simply slide them into a new system. All data will need to be copied. Either way, backup is something everyone will always recommend (fire, theft etc).
If you want an SSD as a primary drive where OS and apps live, you need to reset the entire NAS.
If you buy another NAS, you can set it up with SSD as the main drive and add additional drives where you copy your data to from the old NAS. You can not simply slide them into a new system. All data will need to be copied. Either way, backup is something everyone will always recommend (fire, theft etc).