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

Username	Date	Post Link	Relevance	Offered Matches	Sought Matches
u/671995	2021-05-12	Post	`5`	Russian (Native)	Spanish
u/erebus263	2021-04-22	Post	`5`	Russian	Spanish
u/kitsukaii	2021-04-17	Post	`5`	Russian (Native)	Spanish
u/hippie_st	2021-06-07	Post	`5`	Russian (Native)	Spanish
u/vicvalentin	2021-03-29	Post	`5`	Russian	Spanish

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