It is a standard problem with Krieg set - there is really no decent no-legendary weapon and shield for it, or at least I’m not aware of one.
I’ve made this as an alternative:
But it is not tested for battlemage, so you’re on your own, sorry.
EDIT:
a friend of mine suggested farming Theodin scepter and use some MI shield you could buy in Malmouth Resistance camp after rescuing residents (Hyram).