With only 70,000 miles, I say keep it at least a couple more years. It's barely broken in.
I really like my 2019 CX 5 GT-Reserve with the turbo engine. I have only put 10,000 miles on it in two years though so can't really comment on long term reliability, but I have confidence that it will be a good one to keep for a while.
At 250 HP it has plenty of get up and go, but as an old motorhead I'd sure like it if it had about 50 more HP. It makes all of its torque below 4000 RPM so it has lots of grunt where it needs it.
It is quiet and comfortable, gets 27 MPG on the freeway at 70 MPH which is not best in class but since I'm not putting 1000 miles a month on it is good enough. I live in the mountains and it handles surprisingly well for a 4000 lb high center of gravity SUV.
My biggest complaint is this: Due to the suspension design, you cannot use tire chains or even cables on the stock factory 19" wheels and tires without them rubbing on the struts.
I live on a VERY steep street and even with AWD, if there is any snow on the road or icy conditions I can't get going up the hill and stopping on a downhill slope is treacherous. I only get snow a few times a year but am seriously considering buying a set of dedicated wheels and snow tires. I think that is kind of lame of Mazda not to allow the use of chains in conditions that warrant them. I'd sure like to be able to install a set in the comfort of my garage and remove them as soon as they are not needed.