Open-loop FBW vs Close-loop FBW

[777Supremecist]

Hello everyone,
Can someone pls explain to me how exactly does open-loop fly-by-wire work? I keep mixing it with Boeing's C*U fly-by-wire logic, how is it different from Boeing's C*U FBW control laws? From what I understand, an open-loop FBW system is kind of similar to Boeing's C*U FBW control laws, in a sense that it kind of "replicates" the mechanical feel of a hydraulic aircraft. Also, in open loop system, the FCC does not provide a feedback loop to keep the flight conditions similar to the pilot's original input (tho Idk if Boeing's C*U does that or not).

Here's a quote, "In the open-loop FBW, the displacement of the control column is transferred into an equivalent movement of the aircraft’s elevator, Unlike a traditional hydraulic system, there is a variable control gain unit in the loop which lowers loop gain at higher speed, but there is no adjustment of the elevator displacement based on how the aircraft reacts in pitch. There is no system feedback loop."

How is this different from Boeing's C*U FBW logic? Shouldn't C*U be classified as an open-loop fbw then?

From what I understand, the way it works is open-loop <--> C*U (kind of like an intermediate between Airbus's C* and Embraer E1's open-loop FBW) <--> AIrbus's C* FBW law. To me, it seems like the C*U is kind of like an intermediate between an open-loop fbw and C*.

Here are some of my questions regarding this system:

1) W​​​​​​hy is the C*U FBW logic on the Boeing considered a closed-loop FBW system instead of an open loop?
2) Why did Embraer (which used an open-loop FBW system on the E1) switch to a closed-loop system on the E2?
3) Theoretically, would it be hard to implement an open-loop fbw system on an aircraft that used a sidestick with 0 force feedback (basically a very typical fbw sidestick with an electric trim switch maybe)
4) (Elaborating on Q3) Lets say I want to implement an open-loop fbw system on an aircraft, would it be absolutely necessary that I would also have also implement a force-feedback system for it to be effectively used by pilots. (Basically, can I implement an open loop fbw system on an aircraft that has a typical airbus-style side stick and no force feedback)?