That's how it's always been done
Never imagine that a brilliant performance of a work or of a character is so sacrosanct that you must emulate it in your work. Your job as an artist is to tell the truth as you understand it--it isn't so much to re-create someone else's truth as they understood it. There will assuredly be a stage in your development when your work is derivative of the work you've seen; and I honestly think that's a valid way into a craft that can seem inaccessible in the early stages. "I like Patti Lupone. If I do it like Patti Lupone, I'll be doing it in a good way." There's a germ of truth in that statement. BUT one of the hallmarks of the performers you admire is they are most likely telling their truth in their particular voice. What you and they have in common is both of you have a particular voice. Your job is to go looking for yours.
When preparing a role, I seldom watch someone else in the role before I've made my choices and decisions about the character. I want to be assured I am creating from within my own set of skills, experiences, understandings, biases, quirks, and processes. I have an especial aversion to the temptation of mimicking another performance (unless, I'm imitating--which is its own thing, altogether). I want to make sure the posture, walk, cadence of speech, relationships to other characters, tone of voice, and idiosyncrasies come from my body and from my brain--I want to make sure that the character I have settle upon is "of me."
Bert Lahr's Lion in The Wizard of Oz is iconic. Consequently, it has become the gold-standard of Lions when performing in The Wizard of Oz. When I performed the character, I asked the director, "Do you want me to try stuff, or do you want Lahr." She said, "THEY want Lahr." If I ever have the opportunity to direct that show, I want my Lion to try stuff. Here's why: audiences didn't want Lahr till Lahr did Lahr. They didn't know to want him till he gave them something so splendidly "him" that it has now become the way one does that role. I want for you, actor, to create work that is inventive and potentially iconic.
Sinatra is Sinatra because he opted to sound like himself. I've heard so many singers having *okay* careers--SOUNDING LIKE SINATRA. Find your sound. Find your voice. Sinatra's is taken.
And I get it: we risk complete failure every time we create something out of thin air. We risk utter ruin every time we dare to step outside of the box of the prescribed ways of doing things. But we also run the risk of creating something truly special--that speaks in our own, true voice. You take this risk on behalf of your own art, I guess. But I think you also take this risk on behalf of an audience that deserves to see your best version of the role you're developing.
Any choice you make--that is supported by the script--is at least worth exploring. You may have to yield to a director's vision. You may try the idea, and it may simply stink. But explore the possibilities of truly original characters every chance you get. Conspire with your script to flesh out fully formed humans as yet unseen every time & every show. No matter how iconic the character, approach it as though you are the first actor to look upon the page. And create something beautifully original!