Grids width inside the section
grids with two columns shall have fixed width 60em - check and adjust
grids with more than two columns should have width 100% - full screen
I've done it for 4 grids (2x per SAML IDP and authenticators). It is actually max-width = 50em, so that the grid is not wider then the wide text fields. Those look good to me.
We have couple of other similar grids with one column of names and one column with actions, with are left as 100% wide. Those are the not in sections and I left them. This is because it doesn't look good on its own. My approach would be to add some more columns to those grid, with some extra information, instead of thinking on some strange looking width limit.