Wikipedia has an article listing some of the notable (walking) straight line missions: https://en.wikipedia.org/wiki/Straight_line_mission

edit: and the article already notes this longest possible path from Portugal to China, citing a 2023 article: https://bigthink.com/strange-maps/these-are-the-worlds-longe...

Note that the 2023 article also cites the submission, which is five years older.