Newby trying to connect 4 drives ana a 1tb SSD drive

I have an old WD 4 Bay Nas I plan on putting the drives into a Jonsbo N2 case. I bought a 6 sata capable n1505 mb . I want to use 4 bays with my WD drives 5th bay empty for future and connect my SSD to sata6. I could just buy a seperate

SATA to USB Adapter Cable, USB 3.0 to 2.5 inch SATA III Adapter, HDD/SSD to USB, Hard Drive Adapter, UASP Supported, Compatible with MacBook, PC, Laptop - USB to SATA Adapter (EC-SSHD)

If that would be better than using the sata6 port
I’m looking for advice as this is my first NAS build and I’m not familiar with trueNAS configuration restrictions.

My main use will be to store photos and docs currently on the cloud to my own Nas. I am not a power user but do love learning new technology and hope to expand my knowledge and use of this build after I get it setup.

Use the 6th SATA port rather than a USB adapter.

Its probably OK to use a USB-SATA adapter for the boot disk - but why take the risk?