Bitter learning curve. Absolutely DONE with carburetors!!!

FI can be tuned wrong and lead to rich or lean problems so seriously, carb or FI is not really the issue. Unfortunately, the issue was not caught in time, but likely due to your just being new to things.... it happens when you are new and are learning, and even experts muck it up once in a while. You had an unusually large amount of fuel leakage there if there was 2 extra qts of fuel in there! The carb had to be flooding or the pump diaphragm leaking as mentioned. With more experience, I am sure you would have caught it sooner and things would have been different.

BTW, we had light seepage from the primary fuel needle & seat in a recent new 340 startup. Drove the new engine 20 miles after break-in... pulled plugs and found the front 4 plugs very rich, which lead to the detection of the issue. A new Holley kit fixed it all up. That is just from knowing what to look for and being aware that we were starting with an unknown carb and to be watchful on that... all just from past experience. I would have been just as wary with a new FI system on a new engine.

Have you gotten to the point of pulling the bearings? You 'know' it is ruined bearings but this is your first build...... maybe jumping to conclusions?