Cubase 11 - stuttering video - restart video engine?

There have been previous posts for this - and the codec maybe the issue - I’ve tried all sorts of tricks, different codecs/wrappers - best results come from rendering video out of Da Vinci Resolve

If I close the entire Cubase project and reopen - it always fixes it - at least for a while.
But that could take 10 minutes at least. I like making tea, but also need to get stuff done!

Does anyone know how to restart the video engine without closing the project?

I read Cubase uses its own vid engine these days, rather than QT (from the forum mainly) but I don’t have any detail around that.

This is with OS Mojave 12core late 2013 Mac.