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

Username	Date	Post Link	Relevance	Offered Matches	Sought Matches
u/throwawayaccount062	2021-10-17	Post	`5`	German	Japanese
u/lamusicista	2021-09-20	Post	`5`	German (C1)	Japanese
u/ralon17	2021-09-27	Post	`5`	German	Japanese
u/unikum92	2021-10-16	Post	`5`	German	Japanese
u/capybarabread	2021-11-19	Post	`5`	German	Japanese

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

Username	Date	Post Link	Relevance	Offered Matches	Sought Matches
u/throwawayaccount062	2021-10-17	Post	`5`	German	Japanese
u/lamusicista	2021-09-20	Post	`5`	German (C1)	Japanese
u/ralon17	2021-09-27	Post	`5`	German	Japanese
u/unikum92	2021-10-16	Post	`5`	German	Japanese
u/capybarabread	2021-11-19	Post	`5`	German	Japanese

2 points Unikum92

よろしく。I (29M) am a linguistics student in Germany who would like to have a language exchange buddy. I had 3 semesters of Japanese in the University already but would love to work on it further. Hoffe ich könnte dir mit meinem Deutsch hilfreich sein^{^} PM me if you are interested.