I am just about to reply to this support issue https://wordpress.org/support/topic/make-media-and-text-block-normal-width-not-wide-or-full/

If I have understood it correctly the person is asking how to make Media & Text the standard same width as other blocks.

I am about to tell him that he needs to turn off the initial default Wide Width:

Then have no alignment width selected. As no alignment selected is the same as normal width.

I would also suggest having a Normal width alignment. So that a user can select Normal width to see that they are using the standard width.

ps
Normal width is really not a good word. It could instead be default/standard width.
Right now deselecting width is the same as = default/standard width.

EDIT:
Could be something like this:

Advantage:
There is an default alignment visible in the UI alignment options popup.
Showing that there is an alignment that starts out as default and the user can then just change to any of the options available.
There is always one alignment selected. One can not turn off all alignments.
As turning off alignment is really outside the consistency in choosing which alignment to use.

The wording as I thought about it is the page content width.