when holding a stick the little text in the corner shows up and i can press ctrl and i can change mods, but when i press "m" nothing happens i got the fabric api,litematic and malilib all in 1.16.5,please help

Which keyboard layout do you have?

If you have a different keyboard layout from QWERTY, then some of the keys could be something else, for example on AZERTY I believe instead of M it would be , ie. the key that is in the same place as M on QWERTY.

You can also get to the Litematica config menu via the mod list from the Mod Menu mod, to try if changing some of the keys would work.