Can iPhone 11 Pro bought in the USA work in South Africa?

Hi, I will be in New York next week and I plan on buying the iPhone 11 Pro Max Midnight Green. I plan on buying it sim-free and unlocked.

My question is, will I encounter any problems in terms of connectivity and reception when I bring it back to South Africa and use Telkom Mobile as my network provider.

I read an article on here that was written in 2013 that said South Africans might encounter 4G problems.

(https://discussions.apple.com/thread/5367137?answerId=23153318022#23153318022) Is this still true?

Thanks in advance for any responses!