Lets talk about slow cooking. I saw this video https://www.y

just depends on what you want. with a stew the aim is usually to have the meat flavour the sauce, and have the sauce be a little lighter, because you're drinking it up with a spoon. with a braise you often serve the piece of meat intact on a plate and reduce the braising liquid to an intense sauce, or you shred the meat and bind it with the sauce to stuff it in something or whatever

you can braise on the stove, you just won't get the glazing effect on the top and sides of the meat, and less caramelisation of the sauce. same thing with half vs full submerge. you want a substantial portion of meat to get the effect of browning and you want the liquid to reduce to a saucey/glazey consistency.

oxtail usually gets stewed i guess. i think if you have one big piece of it, braising it with guiness then serving it hot and steaming with the guinness glaze over the top and pickled radishes and turnip mash would be pretty good, cause you can sort of drag the meat away from the centre bone with a spoon