Allow layout builder to co-exist with fields system

I've been trying out layout builder with some content types which already existed on my site and were constructed using the fields system. As far as I can tell, once I activate layout builder, my access to the original fields and their settings disappears and I adjust content display through the layout builder exclusively.

The biggest unwanted consequence I am experiencing with this is that there is some conflict between my original field display settings and those of layout builder. For example, prior to installing layout builder, I had some fields set to display the title heading of the field. In my original setup, it did this in an unstyled way (ugly!). When I installed layout builder, the layout builder allows me to separately set the field title head nicely styled to match my theme (thank you!). However, it does not turn off the original instruction for field titling nor theme the field head, so I end up with duplicate titles, one nicely styled, one not.

Because layout builder seems to deny me access to the field display system, the only way I can think of to correct this is to uninstall layout builder, go back to the original fields, and turn off title display, then reinstall layout builder. That's silly. Somehow layout builder should continue to allow direct access to the previous field settings so I can adjust them as necessary.