I have used this image for the Cover of our Pew Bulletin for next Sunday. My view is that it is sound, good and helpful, and we should bang on a bit more about it. Others have suggested it is just too old fashioned, and I should use a picture. Despite it's Arian Heritage and Dome of the Baptistry in Ravenna is a good option. This Dome from Budapest also appeals. People seem to prefer these triangle images. From the point of view of the Bulletin we do print in mono so the glorious colour is lost.
There is, of course, the old saying that a picture speaks a thousand words. I also know this post is too late, for Trinity Sunday 2021 at least. Would it not have been possible to somehow combine both the text, which I do like, with an image. It is a shame you cannot use colour; although, I do understand the economics of not doing so. The first two images you post are good. Pesonally, I do not like these triangles representing the Trinity, but that's just by two ha'pennies worth.