I don’t know about websites, but i use pc apps for that. HakuNeko can download manhua/manga/manhwa and calibre can convert them into need formats. Here’s HakuNeko link: https://sourceforge.net/projects/hakuneko/ Here’s calibre link: https://calibre-ebook.com/
You can buy copies of Tower of God (not in English yet) and some old Manhwas that were released before webcomics really took off in Korea. Daum and Naver didn't open their webtoon sites until 2003 and 2004 respectively. For example, Totally Captivated is an old BL series that was released in paperback and has subsequently been translated to many languages. You can also now buy digital copies of it on many of the apps listed.