Um. First of all, protein is good for not losing lean mass while on a cut, not just gaining more muscle. Secondly, excess protein basically converting to carbs sounds like pseudo-science, sorry. Excess protein only happens at absurd levels, like 4.5 gram per pound of bodyweight.
So we are in agreement! Mostly. Though carbs was the wrong word.
Though almost nothing I have read at any point agrees on your excess protein amount. Not even close to the same stratosphere, though many don't agree on the limit. Most say somewhere around 1-2 grams per kilogram. And a kg is 2.2 lbs.
This article looks like complete bs from a site that wants to sell shit. It has sources, so Ill give it some more research, but Im very skeptical.
As for the limit, yeah theres not too much of a consensus, though my claim is based on studies that experimented with this and only found issues at that level. I can try to find you some, if you want.