Took my Qashqai in for yearly MOT and service and they identified what they thought was a timing chain issue and said that it needed to come in for a diagnostic. Dropped it off and they had a look at it, said it's not what they thought it was, haven't charged me and said that there's a possible engine knock. I've tried listening for it and it seems that it only happens around 1500-2000rpm if you quickly rev the engine and then take your foot off the gas, like a click sound. I asked the service department their opinion and they said either think about trading in to somewhere like webuyanycar or possibly expect the engine to go in 6 months and need an engine replacement but they couldn't really say. They then said a replacement engine would likely cost about £9000 (which is the current value of the entire car with similar mileage if I bought from a dealership).
Question is, has anyone else had experience similar to this, what did they do in this situation?
Would love to hear from owners and mechanics for their thoughts as replacing the car isn't really my ideal situation at the moment.
(Also needs new brake pads, thermostat housing and bush arms so still looking at £2500 worth of work to be done)
EDIT: Just to add context (thanks u/RuMcGooo) - 1.2 DiG-T Tekna with about 78k on the clock.