We are also doing 3 European countries next week.

My wife and I will be using a hotspot (4G LTE) with a European SIM (Orange network) - perfect for not having to get an eSIM for our iPhones 14s.
Hotspot will cover all of Europe (mostly).

Our 2 sons who have T Mobile will be using their free international roaming (3G) and may end up buying an eSIM for their phones if it's too slow.

If you have newer phones, eSIM is the way to go - no more physical SIMs...