Getting character Z values instead of numerical z values

Please provide a minimal REPRoducible EXample .
See e.g. whats a reproducible example reprex

It is not clear to me what you are trying to do:
did you already create a glmulti model with results in res1 and are you now deriving z-values for a next step? In that case also show how you created the model.
If you use one of the standard datasets of R (e.g. iris) you don't have to show you own dataset (that could be confidential).