@Adam Munekata welcome to BP man! You have a lot of points in your post, so I'll try to hit them all.
You're 100% right, Boston/Cambridge is very, very tough market for cash flow. You are not far off from your cash flow projections, which is just simply the return profile you can expect to get. But as you mentioned points on recession and stability, this is the reason people buy here. You are trading in monthly cash flows for much greater stability, especially when you are talking about markets like Cambridge and Boston (and especially since you are buying more or less retail product 100% leveraged, its going to be tough to have amazing cash flows).
Now in terms of finding "good deals" now, you just need to know how to look at the market. There are certainly listings in Camb/Boston that fly off the shelf today, but if you look closer you'll also see that there a lot of (quality) listings that for whatever reason sit on the market. Rather than getting into a massive bidding war over the "hot" properties, I would look at those that are starting to accumulate days on market. I think it's more evident than ever before. It's a numbers game, and especially now that there is more inventory coming on the market now that the rental market is hurting (which I believe is temporary), I think there is good opportunity to find a good deal.
And finally, I def would not use your standard BP rule of thumbs in the Boston market. The 1 or even 2% rule, or the 50% rule, are just not really relevant to a Class A market like Boston/Camb. Its comparing apples to oranges looking at investors who use these rules in markets like the mid west or the south vs Boston, which is literally one of the most attractive markets in the US. Different ball game here! Feel free to PM me if you have other questions.