The term "RICH" is a very broad term.
A person in the street can claim that he's rich. I can also claim that I'm rich. A businessman who is successful can call himself rich. Anybody can say that they're rich. Like I said, the term "RICH" isn't only used in money, but in other concept of life as well.

Now to answer your question if having 1 Bitcoin this 2023 can make him be called as a "RICH" person, yes. I can call myself rich if I have 1 Bitcoin. It all depends on the person who are holding it. If you let Warren Buffet hold 1 Bitcoin, of course that will not make him say that he's rich because even though he don't have 1 Bitcoin, he's rich already. On the other hand, if an Average Joe, or how should I classify myself, maybe a middle income earner like me has 1 Bitcoin, of course I can call myself rich already knowing that our yearly income if being paid at a minimum wage is around $2,650. 1 Bitcoin is worth ~10 years of working time or even more.

Overall, being called as rich doesn't define by how much Bitcoins you have, but to answer your final question, for me I guess having at least 5-10 Bitcoin can make me rich, but TBH, I can call myself rich already even though I only have 1 Bitcoin or even lower.