Phnom Penh vs. Provinces: Should I worry about regional Khmer variants?

I’m getting ready for my first trip to Cambodia and I'm worried about sounding like I learned from a weird textbook. I know there are different accents and vocabulary preferences between Phnom Penh and the rural provinces. As a beginner, should I be trying to mimic the capital's dialect, or will I be understood everywhere if I just stick to the 'standard' Khmer taught in most courses? Is there a specific regional variant I should prioritize for travel?