I currently use a few filters for Novelupdates and VN Meido that filter out all the Chinese, Korean, yaoi, and smut releases. Copy-paste these if you want to use them. These work on both the series finder and the front page (for the front page, make sure you have “origin tagging” turned on so it says [JP], [CN], or [KR] next to the name).
Completely translated LNs, sorted by last update
Latest LN chapters
! 2022-02-25 https://www.novelupdates.com Filter out Chinese and Korean releases
www.novelupdates.com##tr:has(span:has-text(/CN|KR/))
www.novelupdates.com##div.search_main_box_nu:has(span:has-text(/CN|KR/))
! 2022-02-25 https://www.novelupdates.com Hides yaoi and smut releases.
www.novelupdates.com##div.search_main_box_nu:has(a:has-text(/yaoi|Smut/i))
! 2022-03-11 http://www.vn-meido.com Hides Korean releases.
www.vn-meido.com##tr:has(a:has-text(/\[KN\]/i))