The TTL flash metering with the Metz 386 adapter for Bronica SQ-Ai and ETRSi will function fully, regardless of the presence or absence of a metering prism on the body!!!
If you want flash to be brighter than ambient, simply dial in a lower ISO value on the Metz 386 adapter than the actual film speed; if you want less light than ambient, dial in a higher ISO value on the Metz 386 adapter, than the actual film speed. If you have a metering prism, you can independently set the ISO of the metering prism from the ISO value set on the Metz 386 adapter.
Also with Sunpaks which take the BR-1D adapter.
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.