No LTE

5ge is lte a and yes in some markets its over saturated 

My partner has an android phone on AT&T and doesn't have an issue at all. Is this specific to iphones?

Nope. As mentioned, 5Ge is enhanced LTE but basically LTE. I have an iPhone 12 but never use 5G as it is just not reliable in our area. I have my phone set to LTE Only and calls/speeds are just fine. 5G was nice when it first came out but now it seems that everyone MUST use 5G so the towers in a lot of areas are just saturated and fall back to LTE or 5Ge.

Hmmm I don't have a setting to enforce LTE only like I've seen in other posts.

iOS 16.5. Settings -> Cellular -> Cellular Data Options -> Voice & Data (choose between 5G Auto, 5G On, LTE).

iOS 16.5. Settings -> Cellular -> Cellular Data Options -> Voice & Data (choose between 5G Auto, 5G On, LTE).

The iPhone SE is not a 5G phone, so they likely don’t have any choice. My iPhone XR doesn’t.

The iPhone SE is not a 5G phone, so they likely don’t have any choice. My iPhone XR doesn’t.

The iPhone SE released in early 2022 is indeed 5G capable. The XR is not.

So then it's not a 5G issue?

When did you get the SE? Did you check the settings as I suggested to see if you even have the options under Voice & Data? Do you have a 5G plan and a SIM that supports it? As I mentioned, I don't bother with 5G and just leave our phones on LTE only. We always get either LTE or 5Ge. My wife's phone is an iPhone 7 so she doesn't have any choice other than LTE so there are no options for her to choose from.