Every language has homophones. Even before tones were created, sometimes there are just coincidences. As far as I know, there’s nothing to suggest that the number four and death are inherently related in some way. No one is suggesting that knead and need are related even though they sound the same, and lead (the act of leading) and lead (the metal) may happen to share a spelling but they’re still completely different words.
Sorry, but if you were born in the early 90s, you’re not Gen Z, you’re a millennial. The general cutoff for Gen Z is usually agreed to be about 1997.