Jakob ran 12:48 when he was 20 years old. He is now two full years older, and he has made tremendous progress since then, evidenced by his 7:54 mile.
You are acting as if Jakob only a 1500m runner, managing to do well in higher distances, but this wrong. Jakob is an endurance-based athlete going down to the 1500m.
He won his first Euro xc gold in the U20 division a couple of months after his 16th birthday.
He is the double Euro xc champion from 2021 and 2022. These are a great indication of his endurance capabilities, because he does no xc training but is vastly superior on the 9,5km course (which surely equates to above 10000m on a track) against the best athletes in europe, many of whom train specifically for it
To say that Jakob is not capable of sub 12:40 is beyond delusional, or to say that 5K isnt his best event. He crushed the world elite at the age of 20, in a fast 12:48 race.
The world championships in Tokyo in 2025 is in September. That's the only major championships for him that year, and he will be 24 years old that season. He will have plenty of time that season to go after all the records he wants, all the way from 1500-10000, while being 24 and in his prime.
If he does not get injured, he we almost certainly have tried to go for the 5000m WR, and if he wants to, it's not unlikely that he will be the first man to run sub 12:30.