In the infamous encyclopedic book of Najdi school compiled by Najdi scholars called الدرر السنية في الأجوبة النجدية , we see Wahhabi scholars pronouncing mass takfir on the people of Kuwait.
Their grand Sheikh Suleiman bin Sahman (1850 -1931 AD) says,
ما في الكويت إلا مشرك، أو أخو المشرك
“There is nothing in Kuwait except a Mushrik, or the brother of a Mushrik.”
https://al-maktaba.org/book/3055/2117
and later says:
فإذا عرفت هذا، فهذا الرجل الذي من أهل الكويت، عاص لله بإقامته في هذا البلد الذي هو بلد كفر، لا يجوز للمسلم الإقامة فيه
“If you know this, then this man from the people of Kuwait has disobeyed God by residing in this country which is a country of disbelief and it is not permissible for a Muslim to reside there.”
https://al-maktaba.org/book/3055/2118
The same person even goes to the extent of using poetry to make Takfir on Kuwait and Al Ahsa, as seen in below manuscript image of his work:
Taken from: https://twitter.com/Hafshanbli1/status/1522027240762056704
Wahhabism Unveiled 