There are 3 culprits:
1) Goff
2) McVay
3) Blythe
That's it. Yes, Goff had ONE good throw that should have been a score (though there also should have been a PI flag, but...well, it's the Patriots), but he was consistently terrible all game. Yes, people were in his face after 2 seconds all night (see culprit number 3), but if you take a look at the replays from a birds eye perspective...there was almost ALWAYS someone open that he missed. The tight ends, especially. And for his one good throw, he had at least a dozen that were absolutely terrible.
Ever since Kupp went down, he's looked like a different quarterback. And, given how he seems to want to funnel the entire offense through Reynolds now, even though Reynolds is the worst receiver on the field most of the time, it signifies he's got a problem with tunnel vision.