Excited to have joined the NAS owners club. Now, which HDs to buy & from where - UK.

I've bought a Ugreen DXP4800 to replace 2 x 6Tb external drives (one is backed up to the other). My initial plan is to put 2 x 10Tb in the NAS, again backing one up to the other, and having a 10Tb external HD which I'll keep offsite but update once a week.

Intended use is to stream local content to my TV, photo storage, documents. I'm unlikely to ever exceed 10Tb. No remote streaming or sharing. Simplicity and stability are key for me (RAID currently seems unnecessary for my case?).

Does the above make sense, and if so what HDs should I be on the look out for and from where?

Ta :)