Re: Mojave not being kind to printing
My experience here is during the upgrade, at least. Myself & many I know ended up having to restart/reset/reload the printing system numerous times to get things to settle down. Once it's set, it's OK. But there were issues in setup, with the driver, etc.
Re: Lr needing more than 5 minutes...
Machine is from 2015, so sort of contemporary, but not really. Drive is about 1/2 full. What, I suspect, makes the difference is printing 25 3x2 images on a single A3+, each of which having many edits to them. It worked the week before -- to improve (primarily) the dimension & depth in the B&W prints, more was done -- at which point it failed. Printing one large print is much easier than 25 separate ones.
If you search Adobe or things in general, you'll find folks speaking of the slowness of printing contact sheets. Due to the fact that there are 25 renderings going on.
Nonetheless, that was the issue. And the fix worked. Bugs filed all around...
Thanks for the help
/fred