Nice! i'm making the same - interesting that so many ideas converge. Hopefully we can soon point an GPT6 at all of them and have a super tool. Or else GPT6 can do it without all our helpers...

https://github.com/odcpw/ooxml-cli

Glad to get feedback on what doesn't work or is missing.

I'm also making one for PowerBI - it's in testing. Drop me a line if you're interested.