Really need a CMS in which there is nothing superfluous.
- there are generally no standard fields, all created using additional fields.
At the start, we add several types of material and they assign the additional fields, it can be selects, checkboxes, etc.
Ie Sazava material, we introduce only its name and select type. Below additional fields are shown if they are added. Nothing more.
In Python like this already exists: https://wagtail.io/
P. S. please do not write answers in the spirit: ModX - everything is there, or WP there is a wonderful field and so forth. All these CMS are heavy enough interested in it a little CMS, easy and simple, which would then finished it to fit your needs.
If you know this, share sacred knowledge :) thank you :)