I have a Synology but got my hands on a TerraMaster last year, and all things considered I may well get another TerraMaster if they stick to their current approach: boot Ubuntu off an easily removable USB stick and ship standard Intel hardware.
https://taoofmac.com/space/blog/2024/12/26/2330 (includes all the steps I took to run Proxmox on it as well as an overview of their standard feature set and BIOS)