Sorry, I am not following this statement you made: "The risk of a bike that's long enough for you is the pain you'll experience in an emergency stop." You mean if I slide forward off the seat and land on the top tube?
My own fault for wording it that way. You got my meaning, though.
I've come down hard on the top tube a few times, and my first response was to switch from a 58 CM frame to a 50. The 50, alas, was too small for anything beyond 5 miles. After not riding for a couple of years, I got a 54, which was just right.
When my 54 was stolen (Labor Day, 1981), I rode everything I could get my hands on - Trek, Miyata, 3Rensho, Basso, Raleigh, Fuji, were the names I remember. I just felt I was hanging out over the front wheel too much, even with 110 mm stems. A guy in the shop pointed to a frame they had sold and taken back in trade and suggested I buy that. He also said he could find a lot of used parts that he could sell pretty cheaply to fit my budget. (For example, my seat post may look like a Campy, but the engraving says 'Arius.') I accepted his offer. A few years ago, I fed my measurements into Competitive Cyclist's tool, which is when I found out that at least one person (the one who coded the tool) thought I needed a longer TT than is available from most bike companies.
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You can reframe the issue to: you're between sizes, so you have more options than most people do.
No size will fit you perfectly, but you do have multiple choices. The reason I recommend test rides is that a test ride at least gives you a chance to find out if you prefer one compromise to others. It's a real bummer that you want a bike now, when the supply chain is so messed up.
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Also, the FX3 looks like a nice bike, but my bet is that other companies provide competitive offerings if an LBS has a bike from another brand that fits you well, you may be better off getting that bike.