Regarding hiss, I had the same problem with my Audioengine A1 speakers and eventually traced them to the 3.5 to 3.5 jack cable. I ended up buying the Audioengine D1 DAC and used a 3.5 to RCA cable. Hiss completely gone. The USB connection for the A2 might have the same advantage.
Bass cutoff is a limitation of the speakers size, if I explained it properly 😅 it's there but you can feel it needs more Hiss on the other hand is noticeable at close range, other than that, super small and super loud at the same time 🫡
Your tech review is pretty bad. For a computer/desktop setup front ports are a blessing as a rear ended bass port needs more breathing space. Further you are comparing two different sized woofers when it comes to bass. Which is not a good thing to do.
I agree for the bass port and close to the wall, but I think I said that rear port vent gives deeper bass, and yeah you need to be at least 15cm away from the wall. I compared two different sizes just to show how powerful A2+ are for their size...