That verse is saying that the 4th generation will break out of Egypt.
But you are implying that ONLY the 4th generation will inherit the land, despite what God later told Abraham in Genesis 17:8.
That is reading into the Bible what you want it to say
No, it is what scripture says, about the 4th generation of his seed. What you are doing is making the earthly worldy inheritance the same as eternal, heavenly inheritance.
Abraham was told he would die in the first covenant, Isaac died, Jaocb died, and all the generation with Joseph died. And they knew they would. Joseph told them to carry up his bones because he knew the inheritance was to the fourth generation, AS SCRIPTURE CLEARLY SAYS.
Read what scripture says
Acts 7:2 And he said, Men, brethren, and fathers, hearken; The God of glory appeared unto our father Abraham, when he was in Mesopotamia, before he dwelt in Charran,
3 And said unto him, Get thee out of thy country, and from thy kindred, and come into the land which I shall shew thee.
4 Then came he out of the land of the Chaldaeans, and dwelt in Charran: and from thence, when his father was dead,
he removed him into this land, wherein ye now dwell.
5 And
he gave him none inheritance in it, no, not so much as to set his foot on: yet he promised that he would give it to him for a possession, and to his seed after him,
when as yet he had no child.
Heb 11
11 Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised.
12 Therefore sprang there even of one, and him as good as dead, so many as the stars of the sky in multitude, and as the sand which is by the sea shore innumerable.
13
These all died in faith, not having received the promises, but having seen them afar off, and were persuaded of them, and embraced them, and
confessed that they were strangers and pilgrims on the earth.
16 But now they desire
a better country, that is, an heavenly: wherefore God is not ashamed to be called their God: for he hath prepared for them a city.
17 By faith Abraham, when he was tried, offered up Isaac: and he that had received the promises offered up his only begotten son,