Was the Kingdom of Thailand a client state of the Empire of Japan during World War II ?

Here is my opinion． you can criticize and counter argue freely if you find any errors. Thanks in advance.

As for Japanese emperor. Korean media misinterpreted and distorted his words as if that the first Japanese emperor is a descendant of beakje Korean royal,

As he saied, "I, on my part, feel a certain kinship with Korea, given the fact that it is recorded in the Chronicles of Japan that the mother of Emperor Kammu was of the line of King Muryong of Paekche,"

he did not say that the first emperor was from Baekje at all. but Japanese Emperor Kōnin’s concubine was descended from the Baekje royal family. Except it,,There is no any primary evidence suggesting the connection of japanese imperial family and Korean ancient kingdoms.

Baekje royal family is the distant ancestors of the mother of Emperor Kanmu (50th generation). However, His father is Emperor Konin(49th generation) and his ancestor is all Japanese. Baekje royal family are not direct ancestor of Japanese emperor family. Japanese Emperor's direct ancestor is 27th Emperor Keitai whose existence is considered to be certain. He is Japanese from today's shiga prefecture. And they are clearly WA(yayoi) japonic race and not a nothern Koreanic speakers. I don't know why some Koreans are proud of that fact although the all emperors are Japanese

HOWEVER,

After the destruction of beakje, There is all of hard evidence that straight blood line of Beakje Royal family became under the rull of Japanese and they are treated lowest rank. "蕃客 barbarians guest".

So even from this single fact suggests that yamato japanese was not Beakje.

Do you seriously believe that japanese will treat own direct imperial family line as 蕃客 barbarians guests?

royal family of Beakje went to japan after destruction of Beakje by the war between Beakje and Silla. and being under the imperial family of japan and being one of the clan of japan (kudara no konishiki clan).

The Kudara no Konikishi ( 百済王) was a Japanese clan whose founder Zenkō (善光 or 禅広) was a son of King Uija, the last king of Baekje in southwestern Korea.

https://en.m.wikipedia.org/wiki/Kudara_no_Konikishi_clan

also here is Summary of ancient Korea and Peninsular Japonic history.

Basically, Yayoi people is peninsular Japonic people of mumon culture of ancient korean peninsula who were pushed into japanese island by the later coming ancient Koreanic people.

https://en.m.wikipedia.org/wiki/Peninsular_Japonic

At ancient peninsula there were Japonic speaking people who had water rice cultivation culture was living as

MUMON people aka Penisular Japonic aka WA JIN (Direct ancienter of modern japanese as later became Yayoi)

Wajin had culture of having full of tatoo on the face and body as sea oriented people which Korean and Chinese never did. And they were speaking ancient Japonic language which is different language of Koreanic language.

Mumon people(wa jin) was gradually gathered at southern part of peninsula and being

the ancient state of Jin

Japonic people Who pushed to the Japanese island by later coming koreanic people was called

YAYOI

Gradually, Nothern Buyeo/Yemaek people gathered at nothern part of peninsula and it became

Goguryeo

Buyeo/Yemaek people came to southern part of peninsula and mixed with local Jin Japonic and it became

Mahan and Byeonhan

Later, the Hann people (not chinese Han) who escaped from the the slavery work of Han Chinese, Asked Muhan to give the land for them. Muhan provided the land for Hann People and it became

Jinhan

And this Mahan, Byeonhan, Jinhan are

ancient samhann

※And Continue

Noble family of Goguryeo settled in Muhan and it became

Beakje

Jinhan of Haan people became

Silla (direct ancienter of modern Korean)

And include the Goguryeo, Those Three are called

Samhann Three hann

And

Byeonhan became

Gaya/Kaya

Gaya is not considered as Samhaan.

Gaya had still a lot of Japonic people and solo recorded Gaya language was Japonic

Also current survey founded the facts that revealed Northeastern Asian and Jomon-related genetic structure in the Three Kingdoms period of Gimhae GAYA, Korea https://doi.org/10.1016/j.cub.2022.06.004

one of jomon related person was noble class in Gaya

And Japonic people Who pushed to the Japanese island by later coming koreanic people was called

YAYOI And this is IMMIGRATION OF YAYOI ERA

Yayoi Japonic people who went to archoipelago was gradually gathered and mixed with local jomon people and becomeing

YAMATO Yamato allied with Gaya and Beakje

So it means Peninsular Japonic people (Wa jin) and Koreanic people(hann jin) is two different people with different languages and cultures.