How can I avoid accidental right-clicks now that the Macbook trackpad is so big?

I just bought a summer-2018 Macbook Pro, with a very big trackpad.

The result is that I frequently experience accidental right-clicks when I click but one of my other fingers is touching the trackpad.

Is there a way to change the area where it is possible to double click or do something else to avoid this hyper-sensitivity?

It is especially a problem in Photoshop where I frequently get secondary menus when I just want to move something.

I don't know if it has always existed, but in OS X Mojave there is a trackpad setting that solved this problem for me:

Changing Secondary Click to Bottom Right Corner means that clicking with two fingers no longer works.

It makes the trackpad function more like a traditional trackpad with a right button below it.

I'm tempted to create a plate/stencil to sit on top of the trackpad, to shrink the exposed space -- and see if that fixes these annoying problems. Anyone ever try that? This large trackpad was a bad design decision -- everyone that I know with the same macbook pro hates it.