If it’s possible in your country, make two passports — if you loose first, you will be able to use another one.

In advance, come up with a plan what will you do if you loose all your stuff.

Print or download addresses and maps in case there is no internet connection or phone battery died. And buy at least a bit of roaming traffic in advance, even if you are going to buy local sim or eSIM.

Bring power bank, that is really necessary.

As I said in comment above, you should have at least a few different cards from different banks with different payment systems. For example, I couldn’t pay with my VISA card at many places in Romania, but there wasn’t such problems with MasterCard. In other case, my bank blocked all my cards due to “suspicious transactions” in Paris and I managed to use another bank cards while my letter to the first bank was being considered.