Tower Records Japan has officially announced the 4K Release of “KING KONG VS GODZILLA” on 4K UHD BLU-RAY from Toho: https://tower.jp/article/feature_item/2021/04/01/2501?fbclid=IwAR153nKZshYjSQP2incQ3owdG6USyFTl93HCj_sWhTsDBVcm2WIj-G5YTho
You’ll also find the article from Kaiju Production on facebook too:
https://www.facebook.com/KaijuProductions1974/posts/1727064204142800
A 4K restoration of MOTHRA (1961) was also announced by Toho and will reach some cinemas in japan too.
No blu-ray/4K disc announced for it (for now)