Texting with an iPhone can be done over wifi. Security will vary - most hotels have secure networks requiring a password, but they also rarely change their passwords, or they are something clever like...the name of the hotel. But unless you are shopping or banking online, I would not worry about it too much, to be honest, assuming your personal security (account passwords, 2 factor authentication) is solid (insert plug for password managers). If you think you will be making daily phone calls, or needing to navigate using maps on a daily basis then an international phone plan or an esim/sim card is probably the way to go. There are LOTS of threads here on cell phone usage, just use the search function...