UKC

Each time I've been to the US recently my phone (iPhone SE 2022) has been unable to get onto any available 4G network. This is despite all the settings being correct and 3 telling me it should be fine. Other people seem to have no problems. I can get WiFi without any problems.

Is it best to simply get a US sim card when I arrive, or is there another option I can set up before I go that I haven't thought about?

I don't know the answer but when I go I get a Mint Mobile esim, all done online, good price, no ongoing contract and no physical sim needed.

Even though some of the 4G/5G bands are different in the US vs Europe, most of them do interlap.

I had no 4G issues using SE 2020 when I was last there (or perhaps I was even using me older 6S, can't remember).

So I think the issue might be actually on your service provider. Some do automatically block all roamind data things (nb. you can also enable/disable this your self from settings but naturally this will not override the service provider settings, if the have blocked data-roaming).

That being said, getting a pre-paid US Sim might be the best option (good thing iPhones support two Sims).

Yup eSims are the way to go... only problem might be that I recall you can only have one active eSIM, so if your regular service happens to also be an eSIM, that might stop working (while you have the US one active). But an eSim and a physical one work like a charm.