YouTube VIK-on demonstrated a way to replace the Micron 8 GB GDDR6 modules on a Palit GeForce RTX 2070 card with Samsung 16 GB ones thereby confirming that NVIDIA did have plans to launch a 16 GB RTX 2070 back then. The experiment resulted in the PC booting up, but the GPU crashed under load and posted low 3DMark Time Spy Graphics scores.
https://www.notebookcheck.net/YouTuber-s-GDDR6-memory-upgrade-confirms-NVIDIA-indeed-had-plans-for-an-RTX-2070-with-16-GB-VRAM.516741.0.html