Travel money card

I use Revolut when I am abroad. Really easy to switch between accounts (so you can hold sterling, euros, Aus dollars etc on the same card). Really good exchange rates. I lost my card when I was abroad once and was able to instantly freeze it so nobody could use it (but could still access my own money by using my phone).

We have a Chase online bank account.
No charge to use the debit card abroad and excellent exchange rate.

We use Revolut and Wise for Europe and the Far East

We use Caxton, opened it when we went to Australia.
Sinced then we have used in the USA and Europe.
Also check out the Martin Lewis advise on line, think that's what we did originally.
Sure the PO would be fine, it's the exchange rate they give you need to check out vs others.
Enjoy your trip.