Clutch pedal switch and increased engine braking

[bp2000]

I have a Holden equivalent to the 2012 Aveo.

I have an issue that apparently is caused by the clutch position switch not disengaging when the clutch is out after a hot day. This has two symptoms.

1) cruise control can't be activated
2) the car feels like it has severe engine braking when you lift off the throttle.

Both issues can be remedied by placing your foot under the clutch pedal and pulling back.

The mechanic says it is the pedal assembly which needs replacing at quite a cost, they quoted $1k or something.

Occasionally I get a thunk noise when driving around. Which makes me suspect maybe the pedal assembly isn't the whole story and something is mechanically held up, and there is something stopping the system fully returning the clutch pedal back to the original position.

Question are

1) any opinions if it is likely the pedal assembly or something further? Any good troubleshooting steps?
2) why would the ECU have this behaviour of increasing engine braking when the clutch is put in?

Found one post on an ECU mod forum suggesting this was a thing with no explanation (for another car). I can sort of reason that it may let you drop revs quicker during up shifts, or have better fuel economy during shifts. However I've seen posts suggesting some vehicles do the opposite. Which makes more sense to me because surely when the car is moving in gear less fuel should be required when the system is idle. Maybe it is just a comfort thing cause the engine braking with low fuel injection is too severe when in gear. As a result of the gearing and engine setup.

[bp2000]

I think the problem is a soft clutch pedal return spring. Which seems professionally to require a complete pedal assembly. Seems some people have successfully DIY'd the job just replacing the spring on some cars. See this post https://www.cruzetalk.com/threads/cl...m-again.79394/

Image below.

https://imgur.com/a/YxMJiql

I'm getting to the crossroads with this car and hence not sure if it is worth doing a pedal assembly replacement. Any thoughts if it is a diy job or anyone done it before?