Is is possible to access remote servers in Ranger (cli) file manager using sftp/fish/... protocols, example:
sftp://user@server/home/user
It does not look like it would be possible using Ranger. But you can mount remote filesystem using sshfs
and then access it as every other file on your local system:
mkdir /mnt/server
sshfs user@server:dir /mnt/server
cd /mnt/server