I found the following users who may fit your language exchange criteria:

Username	Date	Post Link	Relevance	Offered Matches	Sought Matches
u/novel_tap_9427	2025-05-18	Post	`8`	Japanese (C1), Korean	English
u/west_studio811	2025-06-11	Post	`8`	Japanese, Korean	English
u/away_blood_9879	2025-06-22	Post	`8`	Japanese, Korean (Native)	English
u/smileyrh	2025-07-09	Post	`6`	Japanese, Korean	---
u/ordinary_end8218	2025-06-24	Post	`5`	Korean	English

Please feel free to comment on the above posts to get in contact with their authors.