I've been looking for an answer for this for a long time and the closest I've found is this SuperUser post however there's no satisfactory answer in there. I have almost an identical situation:
I use Swedish and Japanese as my input language and want to keep English as my display language. Since I can write English with my Swedish input method I don't need the English input. It becomes a hassle to switch between the input methods because I need to remember when I do the Win Key + Space (or left shift whichever you prefer) twice and when to do it once, resulting in me typing in the incorrect input method, resulting in me becoming annoyed over how such a simple setting becomes overly complicated, making me feel sad.
However, Windows 10 does not allow me to do this, it's an all-or-nothing approach. Either you have the display language and keep it in the input list, or you don't have it at all.
If I try to remove the English as input language (Language settings --> Region & Language --> Remove the English input) it also removes it as the display language:
My goal: Keep English as the display language, have only Swedish and Japanese as input methods.
Question: Is this possible and if so, how do I go about setting this? It seems like a very simple thing, yet I haven't found any setting that allows me to do this.