@Rubens @pseudonym58 It may be more of an issue for adult beginners...
I started piano as an adult, while living in Japan, where there is a very high level of familiarity with classical music, even for those who don't play. I think back then I was quite self-conscious about being an adult, but also a complete beginner at the piano. And I had lots of opportunities to play in recitals with kids who were far, far better than I was. At recitals, I never wanted to play the standard classical pieces that beginners usually play, because I felt like all my mistakes, and any modifications, would be on full display. Probably people would have noticed far less than I thought, but given that I already struggled with performance anxiety, it was a concern for me.
I have now been playing for 25 years (yikes!) and I am not anywhere near so self-conscious these days. Whether that's because I play better, or because of the pieces I play, or a bit of both...
Whatever the reason, I have zero reluctance about modifying a piece if it makes it more accessible to me and means I can play it with more musicality.
@pseudonym58 used the word convincing, and as it happens, that's exactly the word my teacher used when we were talking about with a piece I'm working on right now. It's September Song, by Alexis Ffrench, which I think @Rubens listened to when he was doing the Miracles score for me.
I have made various modifications throughout the piece, and I was asking my teacher about some of them, and his way of telling me that those modifications work was to describe them as convincing.
I think another factor might be whether a modification stands out -- if a casual listener notices there's something different, or something missing, then maybe that's not a good modification, but if they don't notice, then I think that's an indication that the modification works.