Yeah, time-series on that scale has unique requirements that can really cripple most DBs.

I'm currently leaning towards python driven dashboards since we can connect them to a REST api which will talk to our data structures and keep everything humming along.

Give Bokeh a try if it's not already on your radar - I've found it to be really useful for composable & dynamic python dashboards: https://docs.bokeh.org/en/latest/index.html.