You are reminding me we also circled an issue at one point where a backend system in Python needed to agree on the same character count length of a piece of content was the client (JavaScript). Another place Intl.Segmenter would've helped.

If I'm remembering correctly, we briefly explored a solution where we told Python "This is a UTF-16LE encoded string" so the count would match, but I think we learned/realized the endianness is actually dictated by the client's machine (Going from memory here). Ultimately we just changed the solution so the client was the source of truth about lengths and counts.

These threads are surfacing all kinds of things I forgot about and didn't add in that blog post. Maybe I need to write another, haha.