NOTE: Highly recommend that you use Hide Spacesuit in Breathable Areas at Starfield Nexus - Mods and Community (nexusmods.com) as your companion will do the same as you. Remove the spaces.
[Menu]
b Use Console Hotkeys=1
s Console INI=StarfieldHotkeys.ini
If you already have a StarfieldHotkey.ini file because you are using another mod like Let's Walk Together - Walk with NPC - Hotkey walking and running speed adjustment at Starfield Nexus - Mods and Community (nexusmods.com), add the following to yours:
[Macros]
spd=sucsm 3
HelmToggle=if player.getav b120b > 0; player.setav b120b 0; elseif player.getav b120b < 1; player.setav b120b 1; endif
SpacesuitToggle=if player.getav b120c > 0; player.setav b120c 0; elseif player.getav b120c < 1; player.setav b120c 1; endif
[Hotkeys]
NUMPAD*=SpacesuitToggle
NUMPAD/=HelmToggle
The Hotkeys can be changed to whatever you want by editing the StarfieldHotkeys.ini. By default they are the Numpad / (Helm) and * (Spacesuit) keys.