Recent study showed the fact Yayoi and modern korean is not related.
Firstly, haplogroup O1b2a1(YAYOI JAPANESE )is originated in Yangtze.
Yangtze is not HAN chinese even not to do with yellow river civilization of china.
But a Austronesian asisn peoples.
So Japonic people from Yangtze is Austronesian southern Asisn People which became The basement of vitnamiese of now.
Yangtze went japan as Yayoi,
Yangtze went south korea as Beakje ,Kaya and wa jin.
They were both speaking the same Japonic language ,Invented japonica rice, also has the same Haplogroup O1b2a1 from Yangtze as Japonic people.
And they were being strongest ally army each other and fight against Silla (Tungus) and Tang (Han Chinese) Which is directly ancestor of modern korean of now, who came from the Noth continent.
Also Beakje sent own royal prince to japan as hostage and asking military support from japan to against Silla / Tang, but japan didn’t send any royal family to Beakje as hostage or so at all.
After the destruction of Beakje by Tungus Silla and Han Chinese, almost all the Beakje royal family and people escaped to japan and left Korea, because Beakje was Japonic people (haplogroup O1b2a1 from Yangtze)and Tungus Silla and Han Chinese was completely different tribe for Beakje. But Yamato /Yayoi Japanese was the same Japonic tribe (haplogroup O1b2a1 from Yangtze) for Beakje.
Also on the other hand, Silla(Tungus) and Han Chinese destroyed Beakje entirely and completely as hell, because they were also thinking Beakje was Japonic people from Yangtze and not the same Tungus/Han people at all. This is reason Beakje escape to Yamato/Yayoi Japan and settled in japan peacefully without problems because yayoi is the same Japonic people from Yangtze.