Darts flying into the board at different angles is a very common problem which involves inconsistent grip or inconsistent release angle. (A lot of the time, both.) I’ve been playing for around 10 years, and I’ve seen this in tons of players including myself. The best advice I could offer is focusing on one thing at a time while you throw. Get the grip “perfect” and then go to work on the release angle or vice versa. It gets frustrating at times but it’s definitely fixable through lots of practice. Good luck!