It is possible to hack pokemon roms only using citra without the help of the 3ds console?

And if it is possible how to do it?

what do you mean by hack?

if you mean decrypt then no and most likely will never be able to without a 3ds

i mean making the game harder without a 3ds

So you mean rom hacking? That would more than likely require game-specific tools written by members of a rom hacking community. Unless you would like to write your own. I don’t think Citra would be very useful in this case.

At least I know one way and that is the only way for now. You can find it here for pokemon oras and sun,moon: https://www.youtube.com/results?search_query=pkhex+for+oras+hacked+thunder

It is possible, but you need to use a couple of tools such as DotNet3dsToolkit(for extracting, rebuilding) and PK3DS(for editing) assuming you have the dumps extracted from the original copy of your game.

U should go look around on GBAtemp. You’re bound to find info on how to, or someone who had the same idea and already done it. As for tools here’s a good link :
https://wiki.gbatemp.net/wiki/List_of_3DS_PC_utilities