Any "weight thing" that I have ever installed usually came where you could open it or split it in half and put it on after the hose is connected.Either clipped together or 2 scews to fasten the 2 components.
The plastic nuts are never a good idea for compression fittings. If you over tighten them, they will crack
Its not as bad as it looks.
Assuming the rest of the faucet was installed properly, a plumber would have a small service call to do . 30 minutes tops.(probably a one hour minimum charge)