Multisite Subdomain Addon Redirecting HELP

Okey as NO ONE helped me on my previous question (he he) I figured things out myself (I think???) and I now came down to this >

[GOAL: To have MultiSite on my addon domain.]

I am working with two domains hosted by Bluehost. One “primary” (example.com) and one addon domain (addon.com) For now I only installed MS on example.com.

MULTISITE
Primary Domain: example.com
Subdomain 1 (S1): site.example.com
Subdomain 2 (S2): addonsite.example.com

S2 redirects to my addon site, but when I want to edit it and press on its dashboard as a Super Admin I automatically logs out and comes to the log in page to addon.com/wp-admin. (Is this normal?)

That’s why I made S1, I thought maybe I could redirect this subdomain to addon.com…. ? Because when editing this one I can do it as a Super Admin an use all the plugins I want (BUDDYPRESS!!) But when I redirect it on my Bluehost it becomes the same as S2, when trying to edit it I come to the login page of addon.com/wp-admin. What should I do?

Also, when working with S1 (without redirecting it on my host site) it only redirects me to example.com (for example when trying to use Buddypress) what am I doing wrong ? (I believe I’m doing everything wrong right now!!!!)