The problem is in your model you have to constantly context-switch back to the function definitions and if a variable gets passed down several times it can be unclear which function to even look at. Typescript remembers the whole chain (as does your tooling, with Ctrl-click, but you still then have to context switch).

I think it's interesting how you slam developers for refusing to learn or conform with team standards, yet you slam them again for doing just that (and at the same time you refuse to learn or conform to prevalent standards). Most teams, like it or not, use JS frameworks, and a good many long-term projects use TS. Developers who want to stay employed learn to do a good job in the constraints they're given and do what they can to steer teams in a better direction, recognizing that organizations would not have the resources to hire them if the existing team did not produce business value despite not being perfect.

You have (apparently) somehow built a business out of insisting clients completely throw out their existing code and rebuild it, with all the costs and risks involved. Not everyone is in a position to do that.