There is an page in inbox https://openwrt.org/ru/inbox/replacingdropbearbyopensshserver
It's in Russian and I translated it to English and put here
https://openwrt.org/docs/guide-user/services/ssh/openssh-instead-dropbear
Now, could you please move the original Ru article to the new path https://openwrt.org/ru/docs/guide-user/services/ssh/openssh-instead-dropbear
Also I improved the https://openwrt.org/docs/guide-user/services/nas/sftp.server page
Please review