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

Username	Date	Post Link	Relevance	Offered Matches	Sought Matches
u/miserylovesblue07	2023-11-12	Post	`10`	Russian (Native), Ukrainian (Native)	English, Portuguese
u/mountain_tell_630	2023-08-21	Post	`8`	Russian, Ukrainian	English
u/medical-historian504	2023-08-24	Post	`8`	Russian (Native), Ukrainian	English
u/ange1dust66	2023-08-26	Post	`8`	Russian (Native), Ukrainian (Native)	English
u/acceptable-cut-2639	2023-08-28	Post	`8`	Russian (Native), Ukrainian	English

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