Why not just give it to the Lithuanian SSR, Rather than have it directly controlled by Moscow and geographically isolated from the rest of that Soviet republic?
Hi there -- not discouraging further responses, but you may be interested in some previous answers on Kalingrad:
https://www.reddit.com/r/AskHistorians/comments/5zaa1b/why_does_russia_control_that_little_chunk_of_land/dewyk42/ from u/kieslowskifan
https://www.reddit.com/r/AskHistorians/comments/63cha5/what_happened_to_the_germans_in_areas_such_as/ from u/kieslowskifan and also u/kaisermatias