.Xr dma 8``` should be added to the See Also list, too. This should not be MFCed, since 10-stable does not have dma.
This is probably better like the comment, "instead of". I suspect that is more common and easier for translators.
"in favor of" usually means the second thing is better than/preferred to/replacing the first. It is kind of confusing here.
Sometimes difficulty in simplifying a sentence means that it is trying to say to much or working too hard to get there.
This example shows how to use .Xr dma 8 as a replacement for .Xr sendmail 8 :
That could be even simpler:
Using .Xr dma 8 to replace .Xr sendmail 8 :