Remmina RDP via proxy

Set option Advanced -> Use system proxy settings:

Check:

$ cd ~/.local/share/remmina
$ grep prox *srv01*
useproxyenv=1

Run remmina:

export https_proxy="socks5://[IP-ADDRESS]:2080"
remmina

Additional info:

org.remmina.Remmina - 1.4.31 (git n/a)