Alchemist (Gun Chemist) LV 20 Build Advice

[Nosta]

I am going to be starting a long campaign soon and I'd like to flush out my character as a level 20 build so i know what My plans are

I want to play a Gun Chemist Alchemist mostly cause i like the flavor

I Need Advice on my Race ( Either Human or Teifling )

and I'd like help picking out my feats and my alchemist discoveries as i am unsure what ones i'm going to want or will be needed to keep being a decent help to my party

[Nosta]

Can anyone help?

I Figure for Feats most will be Range base with a couple extra Discoveries

but its the discoveries i need Advice on

I want a mix of Damage and Utility bombs for my gun