Work keeping an eye on Chris Laffra's work in this area - he did a Python in Excel demo [1] a few months back, and while sheets aren't in his ltk framework [2] yet, the work he's done on reactivity-in-python-on-the-web there is really promising.

[1] https://github.com/laffra/excel-in-python [2] https://laffra.github.io/ltk/