Suckless's simple terminal how to configure alt gr and single keystroke for tilde

Question

In Suckless's simple terminal (st) I can type the tilde ~ by pressing the keys alt gr and 4. But with alt gr and the key to the right of the ñ key, I have to press twice this last key, I want to use alt gr and a single keystroke of the key to the right of the ñ key.

I can do it on other terminals and applications, for example xfce4-terminal, Firefox...

Details:

• Keyboard: Spanish, example: https://assets.ltkcontent.com/images/spanish-keyboard-yd.jpg.

• Operating system: Arch Linux

• Window manager: i3wm

• localectl status command output:

    System Locale: LANG=es_ES.UTF-8
        VC Keymap: es
        X11 Layout: es

I don't know If I have to modify the st config files.

Thank you for your help.