I have reviewed several Realtek RTD1295 TV boxes with NAS and HDMI input functions such as Zidoo X9S and EWEAT R9 Plus, and those were quite capable devices with a rich feature set, but Realtek has been working on a new higher-end RTD1296 SoC for quite some time. It comes with the same CPU and GPU, but has a larger package with more peripheral interfaces.
I received the screenshot above last December, but the information does not seem to have changed since then. Realtek RTD1296 is equipped with a quad core Cortex A53 processor, an ARM Mali-T820MP3 GPU, and the same H.265/VP9 video engine as RTD1295. However, the new SoC adds one extra RGMII (Gigabit Ethernet) interface, one more USB 3.0 port, one extra SATA interface, and offers higher DDR bandwidth. The PCIe interface would also allow you to use more than just two SATA drives.
Charbax got in touch with the company, and shot a video showcasing their various RTD1296 solutions include and Android TV STB with Voice Assistant (not the Google One yet) which allows you to turn on the box, PIP recording for game streamers on YouTube, Twitch…, and some Synology and QNAP NAS based on RTD129X (exact part not provided).