This passage in English looks so different from the passage I am reading in the original Hebrew.
In Hebrew, let's start with verse 2.
ושבח אני את המתים
and I praise/hail the dead
who even/already died
from the living
אשר המה חיים עדנה
who are living yet
and good(better) from the two of them
את אשר עדן לא היה
are who not yet exist/live
אשר לא ראה את המעשה הרע
who not seen the evil deeds
אשר נאשה תחת השמש
who has not done-work under the sun.
I don't know how your English translations work but in the original Hebrew, verse 2 and verse 3 are the comparative duet of two sides of the coin.
Verse 2 says blessed are the dead than those who are actively alive.
Verse 3 says better of the two is one who is not even born, does even yet exist.
אם יוליד איש מאה
if having-children a man a hundred
ושנים רבות יהיה
and many years he lives
ורב שיהיו ימי שניו
and many which are his days
ונפשו לא תשבע מן הטובה
and his breath not fulfilled from goodness
וגם קבורה לא היתה לו
and also burial-grave has not he
אמרתי טוב ממנו הנפל
say I better than he the fallen
Note that the last word [הנפל] Ha-NeFeL is cognate of word of the same Hebrew spelling (Ha-NFaL) the singular for the famous [נפלים] neflim. [הנפל] HaNeFeL is the only occurrence of the Bible conjugated this way, and no where else in the Bible is the word [נפל] used to connote fetal miscarriage. I highly doubt this word should be correlated to miscarriage.
I would say, the passage says that it is better to be among the fallen, the outcast, those rejected from salvation, than to be one who is unfulfilled, and who dies unburied, regardless if one lives in longevity and has a hundred children.
IOW, blessed/happy are the poor in spirit.