Managing skills and techlead and IC skills are pretty different disciplines.

Being 50/50 makes it hard to advance/develop in either one of them significantly.

The biggest issue is that management requires a lot of "wasted time" paying attention to whats going on around you and IC skills require a lot of "heads down time". It's a big fight between those two modes.

I've done it at a startup but it required doing most of my IC work after hours. Which isn't that sustainable.