Terramaster vs. Synology for first NAS

I am not super handy with building pcs so am a bit wary of going the DIY route. I've also used a Synology router for the past 7 years so I know their quality.

My use case is solely photo and video storage (I'm a diver, basically storing and sharing my underwater experiences), preferably with RAID mirroring. My current library is at 2TB and I estimate I'll need 6-10TB over the life of the NAS.

My budget is 400-500 USD including drives. I've been looking at the Terramaster F2/4-212 and Synology DS223. Would love to spring for a 423 but don't have the money. Have also looked at Buffalo LinkStation 220 but heard they have a bad reputation. Any thoughts? Please keep in mind this is mainly for storage and casting videos to my smart TV, nothing else

EDIT: I ended up buying the QNAP TS 464. It's most likely overkill but I wanted something I could grow into