When we produce a Layout, we can control the patch size that displays on the Legend item, but not the patch style/shape, because that's controlled by the symbology definition.
Outside of a Layout (e.g., the Contents Pane of a map view, the Create Features & Manage Templates panes), it's the reverse: You can control the patch style/shape, but not its size.
This causes a huge (pun not intended) issue where different parts of the UI don't allow enough space to adequately see the symbology of the element you're working with.
In a current project, I have multiple different line symbologies where the arrowhead on the line is identical (or near-identical), but the body of the line is very different. See example below, which has two different kinds of features meeting:

Here are their two options in the Table of Contents in Map View:
An identical issue crops up in the Create Features and Manage Templates panes, which makes it much more difficult to tell at a glance than it should.
Even when I try to change the patch style/shape, in hopes of being able to see a bit more of the line under the arrowhead, the extremely cramped space means I just get a jumble of elements, rather than a coherent symbol, as seen here:

Back in the ArcMap/Desktop days, I could actually set the patch sizes for the Map View Table of Contents, but I have yet to find this anywhere in Pro, despite a few weeks of searching off & on:

Personally, I'd even be content if there could just be a project-wide (or less happily, an application-wide) setting to set the patch size for all non-Layout elements.