Question about the Universal Circle

Could the UC be used as a sigil to summon any entity whatsoever? Suppose you don’t have the sigil for a certain spirit and you want to summon it. Could it be possible to use the UC to summon it? Like a portal or something…

Yea, sure.
When you are evoking you open a portal anyway, with or without the UC.

It is good to know what you are summoning and how you will summon it.

Ive been doing this, trying to get in touch with this Malzaz Hyroth dude…