I think we should talk! :) From your description I know exactly where you work and which other Python based system you're talking about )

I have been in the industry for 20 years myself as a quant, mostly using Excel as a "glue" layer indeed, and I worked with the Python based "clone" you mentioned too.

For the last two years I have been working on a platform to fix exactly the pain points you are talking about.

Amazing how your post sounds almost like as if I wrote it myself before I started working on this project :)

Please, take a look at https://ellx.io I would be more than happy to discuss it in detail: dmitry + at + ellxoft.com