I bought some time ago a 2nd hand MBP: MacBookPro11,3 (15" quad core i7 2.3GHz 16GB RAM 500GB SSD)
it came with Catalina, and thought this would be great for continuing using Davinci, because I got stuck with my other MBP with less specs..... and Sierra OS.
So I'm happy that I can use Catalina on the 2nd hand MBP, and continue to update Davinci this way, and still can use Thunderbolt 2.
Btw.... I have a genlock in a Commodore CDTV !

I get the impression you like the analog broadcasting "way" and not the digital "way" ?
I thought the digital version of broadcasting was easier to do, because you don't have to couple everything to a genlock.
Editing on tape could be done with a flying erase head, although I noticed that it was not done frame exact...
Digital was an improvement for Never The Same Colour I thought....
I remember there was a big difference in quality watching US tv series that came from tape or from celluloid on the Dutch tv here.
What I notice that most professional VHS vcr's don't even have component video output...
Also VHS to digital: contrast and colour is mostly not correct, so I use the pipet (black + white) function in Davinci, which puts all nicely on track and only needs some fine adjustment, with Davinci it's a easy workflow, which I never found as easy to achieve with other editors.