That's not true for over two years. Capped by EU at 19 eurocents a minute. And 70 dollars is pretty expensive, I think you should check if there aren't better deals available (I assume it's CZ?)
https://ec.europa.eu/commission/presscorner/detail/en/MEMO_1...
Re:RasPBX Installation for Beginners
by jbverschoor on Friday November 26, 2021 @05:11AM
(#29348908)
Within the EU, you will not pay more for being in a different country.
Data and voice may not cost more when roaming
Data costs vary a lot across the EU. I pay 70 dollars a month for unlimited data with unlimited speed, for example.