When you start something with “I” or “My” as in “I think” or “My opinion”, the I/My sort of tells us that it’s YOUR thought or opinion.  Meaning it belongs to you.  Meaning it’s personal to you inherently because it’s yours.  Meaning you don’t need to say, “I myself” or “I personally” or “My personal.”  We get it.  It’s yours.  You only need one word to delineate that.
These idiotic redundancies only make you look like some kind of windbag douche tard who thinks more words = smarter.

“I personally believe that I myself have a personal opinion that I  myself personally believe myself personally…”

No.
“I believe” or “My opinion.”
That’s all you (yourself personally) need.   Idiots.