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

Username	Date	Post Link	Relevance	Offered Matches	Sought Matches
u/youreanewsongbaby	2021-08-09	Post	`5`	English (C1)	Russian
u/mformero	2021-07-15	Post	`5`	English (C1)	Russian
u/utled	2021-07-06	Post	`5`	English (B2)	Russian
u/ok_net_8348	2021-08-25	Post	`5`	English	Russian
u/eyjafjallajokull2000	2021-07-15	Post	`5`	English (Native)	Russian

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