I shoot a Canon 5D4 DSLR and last year got the Canon R5 mirrorless. I have been able to configure them both pretty similarly using custom menus. I've had the R5 out on several outings but not yet for storms, but I have no concerns it will be any harder to use than my DSLR. It is actually a faster workflow for almost all situations.
The features in mirrorless such as in body stabilizer, exposure preview and tons of info in the viewfinder, electronic programmable lens rings, electronic shutter option, etc. were new to me but I find everything else very similar or even simpler to use than my DSLR. After a couple shoots I felt I had mastered those.
Hopefully after a few weeks you will feel the same about your Z6, the Nikon mirrorless are quite nice. I think Sony is at a lens design disadvantage with the flange distance on their mirrorless system. Canon and Nikon both went with flange distances that should make lens design less complex and more cost effective. The RF glass is incredible and can usually do resolve more and at better focal lengths (for zooms) than the EF counterpart for this reason.
Not sure about the Z6 options but on the R5 I am able to disable EVF or screen or both for different shooting scenarios, and find the battery lasting to within 80% of my DSLR with IBIS set to only be active when shooting. I'm seldom running out and I have plenty of batteries anyway.