TinaCMS is great :) We differ from them and others in this space by taking the approach of making changes to code that the dev team manages (rather than markup like MDX). The tools are solving separate use cases, the one is managing content (which can be interactive but is mostly static), and the other is editing UX copy integral to the web app (which is usually inside react code for example)

We see a lot of opportunity in managing resource in git and are betting that the industry is going there, so shout out and love to the TinaCMS team and other players recognizing that git is where app resources should be managed.