Dear Danne, THANKS (really) for your guide and your patience!
You can start two or three Mlv app apps in prallell to speed up conversion.
That's VERY interesting:
sorry I can image it's a dummy question, but how can I run 2 or 3 MLV App apps in parallel? Some script from the Terminal? Or via Switch? (Up to now I can simply run a single window of that app...)...Now I know: Script Editor

Great advice, Danne, thanks a lot!
For proxy workflow you will still need dng files in the end either virtually or physically exported. [...] Don´t see why you don´t want the dng folders if you are using a proxy workflow in resolve.
[I want to give you an asnwer about this, but I honestly warn all the people in the forum that the following section is boring, not-technical and unuseful, so
you can happily ignore it 
] Actually I don't plan to follow a regular proxy workflow in Davinci, but simply use a prores proxy version of my MLVs, because my current project in based on about 3500 MLVs that means around 34 TB stored in a single 8-drives external RAID6 thunderb.2 full as an egg, and in my 2nd external RAID I haven't enough free space to store all the converted-DNGs. Surely I could use MLVFS but it means keeping the 1st RAID always on, that's I'd avoid for various “safety” reason (first of all the content's safety). It's a huge project to handle for a newbie total-indie like me, mainly because I have NO screenplay: in fact the footage is a sort-of-documentary thing simply based on a concept, not on a story. My “freely-artistic” approach (clearly this is a non-business thing) is “discovering” the form of the film (the screenplay) directly from the “timeline-lab”, where I hope to understand which (FEW!) shots to keep, and which others (many, I hope) to cut out. For the few “survivors”, I finally will do the actual MLV-to-DNG convertions, and this selected DNG-footage will be placed onto a pretty fast internal 4-NVMe 8TB RAID (should be sufficiently roomy). Then I'll redo the editing following the former proxies-based editing. It's not actually a workflow... i.e. it would not have been strictly efficient for an eventual paid job
