Paint the car yourself

Hello, I would like to give my Astra the last painting and free him of rust one last time. I have rolled him once with synthetic resin varnish, however, this looked so modestly from that I have painted him after a few months hobbyally. So everything sanded, spat, degreased, primed and again matt black synthetic resin jingle over. Well, since the rust on the fenders has increased very strongly soon I want to exchange all parts and again, the last time, paint. However, since the black matt goes on the crack after 3 years and every second one so drives around it will be a different color. First I want an extreme neon green or just white. The question is now Matt or shine? Do I get gloss varnish as a not varnisher just like matt varnishes or will it just look like garbage? Art resin or acrylic? If I paint with acrylic varnish it doesn’t have to look like anything else, so the whole old synthetic resin paint, or? And how does it look like clear varnishes on matte varnishes? I am not a painter, so I don’t have to look like a car, but it doesn’t have to look like a job.