The idea of a stir fry is that it’s quick so the vegetables remain ‘al dente’
In a slow cooker you would end up with sweet gloop.
A good frying pan will suffice instead of a wok.
Try making your own stir fry sauces with chilli, garlic, lemon, honey, ginger and soy.
Fry the meat and onion first, then add the veg, fry for 3/4 minutes then stir in the sauce.
Sesame oil gives a great chinese flavour.
The packet ones are very sweet.
A slow cooker however will make outstanding spare ribs.
Fry first to seal now add them to the slow cooker with a jar of spare rib sauce or make your own.
Always add a star anise for an authentic flavour.
5/6 hours should do it.