Instead is a weird modifier. It takes some getting used to. But once you do it's pretty awesome! Have you looked over the "Instead" entry in the REG? That might be really helpful for advancing your understanding of how it works.
Yeah I looked at it before asking. I still wasn't clear on the control issue. I guess it came down to whether instead changed the card to be insteaded's text and replaced it with a new ability or if it substituted the instead ability instead of the original. If that makes sense.
From the REG
The instead modifier indicates a triggered ability which replaces an activated effect or event. It does not undo the
effect, as with a prevent or negate, but instead replaces the outcome such that the
original ability never took place,
and the new action or ability triggers instead.
I guess this portion kinda answers where my confusion was since I was confused on whether it changed the original ability to the new one or what is outlined here. There is some room for misinterpretation but I blame my confusion on thinking of how "hack" effects work in MTG.