Better is an opinion. I can’t tell you what’s better for you.
But, if you do something like Biology with a Zoology minor, you’d probably have alot of overlapping classes that you could get your minor with only a few extra classes if you plan right from the get go. But, if you do something like Math and Theatre, you may need alot more extra classes to make it work – depending on what you did for your general education.
It’s certainly doable – I know someone who double majored in Bio and Music, but it took an extra year of full-time schooling (5 years instead of 4).