So minimum regardless should remain at the default 17x13?
no - that is why I asked again and again for your screen size setting.
the minimum map size is the screen size. If you increased the screen size, then even 17x13 is too small.
for example a game set to screen size 1056x816 pixel will require a minimum map size of 22x17 tiles.
If on the other hand you reduced the screen size, then you can use smaller maps - reduced screen size just has a problem with some menues due to being too small for all info.
EDIT:
and you don't have to use all that size, you can make a frame of black borders around smaller rooms - those black borders just have to be tiles, the map itself can't be smaller than screen size
EDIT2:
In case of RMMZ, the screen size does not need a plugin to be set, it is set in the advanced section of system 2 of the database, please check there.