2014 Mazda CX-9 continuous engine problems...Help!

We got a 2014 Grand Touring about 3 years ago. Last year it started making a knocking noise in the engine and kept dying on me while switching gears. Took to repair shop and ended up spending $6,000 on it. Seems to be same problem again a year later. Same clicking noise and it died on me after coming off of the interstate. Thankfully it finally started back up and we immediately took it back in. Shop is covered up and can’t get to it for 3 days. 3 days later we call and they don’t know what the problem is but they have not taken the engine apart yet. Another symptom is that even though I put the pedal to the metal it just wouldn’t “go” and drove sluggish. After that it just died. NO ENGINE WARNING LIGHTS came on this time OR last year when it did the same thing. Last year the timing belt was changed and a list of other “things that needed to be done” that ended up costing $6 grand. I’m just OVER this car at this point and I’m ready to trade it. It has a little over 100k miles on it and had about 80k when we bought it from Carvana.

At my wits end! Anyone else with this problem?
2010 CX-9 GT
There is no timing belt on this engine.

The big issue with these engines is the water pump, which can destroy the engine when it fails. Outside of that it's been pretty reliable based on the postings here. I haven't had any issues.
We had that replaced last year along with timing chain. Hubs says timing is out of time. Still at shop after a week!


Work In Progress..
'18 CX-9 Signature
Any chance they provided you with an itemized list of what they did last time? I'm asking because it sounds like this shop is taking you for a ride. $6k is a LOT of money to spend. It's possible that they milked you for every dollar they could last time, and they could be trying to do it again.

If possible, get a list of services they did last time (preferably the original invoice), then contact a few 3rd party/independent shops to see what they have to say. Most likely they'll ask to bring it in, but you may get lucky with a mechanic who has dealt with something similar before. You can also post a picture of the invoice here to get more feedback from others who may have had similar work done. Good luck.
If they did $6,000 worth of work and within a year you have the same issue it should be under at least a one year warranty. One thing is for sure, if they are not fixing it under warranty I'd get it the hell out of there and see them in small claims court.