I have been trying to get the latest version of the fonts downstreamed and I am a fair bit wiser by now. Through https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/6272446 and https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/6281390 it should be fixed for ChromeOS.

Android has a different fallback system and it seems I will just need to fix it here: https://android.googlesource.com/platform/external/noto-fonts/

For this I created this issue to collect some feedback. At the moment it seems to have only Symbols, no Symbols 2, and only Regular Subsetted: https://android.googlesource.com/platform/external/noto-fonts/+/refs/heads/main/notosanssymbols/

How would you suggest I update this?

I guess updating the Google Docs fallback is something completely out of my hands, being fully internal, but as the packages/ebuild have been updated for the ChromeOS inclusion that might be easier to handle. I have no way to know how this is handled internally...