There are no stupid questions. I'm away on holiday outside EU and I may need to call our insurance company to get medical support for a child.
I guess I could just use Skype, but I'm taking this as an opportunity to figure out if someone better exists.
Get a local SIM or eSIM when you arrive. If you're dealing with insurance, you might want to be able to receive calls too. Regarding privacy: good luck.
I use Mobile VoIP. It’s a wrapper for which you need a separate subscription from one of the many voip sites. Go to MobileVOIP.com you should see a list of such providers.
I'm currently using budgetvoip, but look through the list when my balance runs out, and find one that has good rates for where I want to call. Some of them have desktop app support, if that's something you want. I have used voipyo and telbo in the past, but I'll switch if I find a different provider with better rates.
I'd look for getting a SIP number and use that with some softphone app.
Your ISP could be selling those and there are some companies that sell them, ususally for businesses, but there's smaller offerings for individuals. Usually paired with stuff like mail2fax, fax2mail, etc.
Not sure what you are looking for, do you want to call landline European numbers from another continent? Or do you live in the EU and want to make calls to landlines in other EU country? If the latter, please define "privacy respecting" because if what you want is for the service to not log your calls, I'm afraid they are obligated by legislation.