Hi FatherPaddy69,
I'm sorry that you're inconvenienced by the surrounding Pokemon spawns near Mahogany Town, and I can understand your frustrations on this.
As hahahaka has mentioned, there are wild Pokemon around level 30 around the Whirl Islands. After defeating Mahogany's gym, you'll also have access to the Ice Path and afterward, Dragons Den, which has wild Pokemon from around level 50. After unlocking Dragon's Den, you should have no issues training up a full team.
I would also highly suggest battling all the NPCs up to your story location, and after beating the Team Rocket HQ in Mahogany Town, your Pokemon should be high level enough to successfully defeat Pryce and move onto Blackthorn City, with Dragon's Den available to you.
I hope this information helps you, and I wish you a good rest of your week!
Kind Regards, Astraea.