Upgrading Xiaomi router 3g (v1) to 21.2


I've tried to upgrade my MI3G from 19.07 to 21.02 but I faced issues with 5Gh wifi. I was seeing a few disconnections per day so I decided to downgrade it to 19.07 which fixed my issue.

I would like to have the latest software from 21.02 repository.. what are my options?
Did someone was able to fix wifi issues?