Pex pipe depending on the type is strong. There are different types beside the orange and blue at the big box stores. THE issue with Pex is the fittings they are not as robust not do they resist the higher impact effect (pipe hammer) of rapid pressure changes.
Lots of common sense rules on this. a good rule of thumb is psi rating x .65 is max working pressure. This allows for a good safety factor. Also, all p[lastic to metal connections should always be a plastic male adapter into a female metal fitting. That way if the plastic does expand it has the metal to resist at the transition connection.
Virtually all PEX connectors are male. Even SharkBite internally. I do not know where you got your idea of expanding or weak connectors.
Three types. PEX A, B, and pretty rare C. The Borg carries B. Red, Blue and white. Never seen orange.
PEX A, B or C - Understanding the Differences :: Apollo Valves. It is basically HDPE and very tough.
" In accordance with ASTM F876, the minimum hydrostatic burst
pressure for
PEX pipe is 480 pounds per square inch (for 1/2-inch
pipe) and 475
psi (for 3/4-inch
pipe and larger) at 73.4 degrees F."
If I had my choice, I would use A. Even for the Milwaukee expansion tool ( $400) it looks like the better system as it can have fewer connectors and their ID is the same as the pipe. Manual tools are more like $100, similar to type B crimper's. But A is a bit more expensive as it is only a couple of brands.
PVC and CPCV are also very tough, but really fall off with heat. @ 140 F it is only 20% as strong as at 72 degrees. Basically working pressure of under 80 for schedule 40. Now one's DHW should not be that high and neither is our air lines. Very easy to work with and no special tools. It is not recommended for DHW even though the Borg sells it as such. ( usually against code)
PEX and PVC both break down with UV light so should never be left exposed. Another win for plain old copper! It would be hard for me to understand someone with minimal workshop skills such as a woodworker to not be able to sweat copper.
There are contradictory numbers given for lifespan. From a low of 25 years ( sounds like plumbers looking for work) to a more reasonable 80 to 100 years.