It's a bit silly that the easiest way to do a reconquista of the Americas is to forsake reconquista
I got the Reconquista achievement shortly after the launch of Iberian Twilight, while Infamy for protectorate wars was still bugged, so I recently decided to try to do it again legitimately.
It was pretty rough! You get a ton of infamy and have to constantly be on the watch for US and Britain intervening. I'm not here to complain about it being hard though, it should be, Spain reconquering her colonies is pretty absurd and should be difficult.
I did another game as Spain, this time deciding to go for normalisation.
I did treaties with all the former colonies, recognizing their independence, usually in return for investment rights and a power bloc embassy. This, in addition to the bonuses provided by the JE, allowed me to pretty quickly get them all in my bloc, a sovereign empire, and then I was able to turn them all into subjects. All of that significantly faster and with way less infamy than when I pursued reconquista.
Of course, this didn't allow me to reorganize the colonies and I didn't get the nice bonus at the end, but it still felt wrong that this was easier to achieve than when I decided to actively pursue it. Maybe the Reconquista JE should provide just some small bonus while active to avoid this.