If your son is doing well at school and behaves well for the teachers, and takes it out on you at home, to a large extent I think he's doing ok!
You are that safe space at home, it's hard for mums of teens for that reason and you do feel resentful sometimes they are lovely to the rest of the world, but that's better than him doing badly at school and threatening to drop out. So, that's a good sign I think.
Now if you can just get a bit more co-operation around the house (which I struggle with myself, good in school holidays, but after school it's hard after clubs/activities to get them doing the washing up) and some more realistic expectations around money, then that might help.
I also agree that having mentors/colleagues/teachers/youth club leaders around to encourage him is very very important. Perhaps he could volunteer somewhere on a Sat or Sun in an area he likes (animals, sport, charity shops). Mine get a lot out of other people valuing them and their time and it fosters a sense of independence.
Obviously if he can get paid work, great but I don't think in our high street there are shoe shops paying 14 year olds to serve in them. Even my students at uni (aged 18 upwards) struggle to find part-time work that is consistent these days, although most do eventually find something. Supermarkets are good for 18 plus. Perhaps some local independent retailers or cafe owners might go under 16, but it is no longer the norm. The forms I have helped my kids fill in recently have all said 16 or even 18 plus, even finding voluntary work for 14 year olds is quite difficult.