iphone 11 better connection on 4g than 5

I'm not surprised you're having issues with 5G on your iPhone 11 since the iPhone 11 is NOT a 5G compatible phone.

The iPhone 12 was the first 5G compatible iPhone...

If you're seeing in indicator that says "5Ge", that is not actually 5G. it is AT&T's enhanced LTE network they refer to as "5G evolution". It is 4G, not 5G. "5Ge" is nothing but a marketing gimmick.

Do you have AT&T as your carrier and see 5Ge on your phone? If you do, that's a marketing gimmick as 5Ge is really 4G LTE slightly enhanced.

KiltedTim is 100% correct in telling you iPhone 11 is not a 5G phone. It does not have a 5G radio in the phone, so you cannot connect to 5G at all on your iPhone.