Normal spaces are disallowed name characters ingame, but not character creation. Just as special characters are disallowed on creation but not ingame...

Your best solution is to use unicode alternatives such as "1/3 space" and "half space" etc. It's easiest to copy paste the special varient then type the rest of the name around the "space" (or premake the intended name and copy paste it in), you can see how it looks before applying the name change so by all means check what works, see if you like it before you commit. you c*so use most emoji in your name.

I use this site for spaces. However if you are on windows you can simply open your start menu and type "Character Map" to find a native program that has most classic universal symbols listed.

jkorpela.fi/chars/spaces.html