You laid it all out pretty well in your original post.
I don't know if this helps or not. I watched the whole game of Titans vs 9ers this week because they're our next two opponents.
Marquise Goodwin was getting open and catching everything Garropolo threw at him.
Is that because the Titans secondary isn't good, or because G and G were playing very well. Shrug.
On the other hand, they made the 9ers kick a LOT of field goals instead of TD's.
All things being equal, if it was my FF team, I'd go with Goff just because he's a Ram. If I'm going to be wrong, I sure don't want to be wrong with some other team's QB.
BUT, are the Rams now transitioning to Gurley + D mode? Is McVay starting to ask a little less of his 2nd year QB, with colder weather and playoffs approaching?
Flip a coin. Go with that. Then you never have to 2nd guess your reasoning. LOL.
Ramily!